CA Well Driller cheat sheet

Borehole diameter must leave annular clearance for casing, centralizers, and seal: a common rule is at least 2 in (5 cm) of annular space on each side of the casing for a proper seal and gravel envelope.

Cable-tool (percussion) drilling advances by lifting and dropping a bit; samples are bailed, and the method suits unconsolidated alluvium and boulder-bearing formations but is slow in hard rock.

Mud rotary drilling uses circulating drilling fluid to cool the bit, lift cuttings, and hold the borehole open; fluid weight must exceed formation pore pressure but stay below fracture pressure.

Air rotary and down-the-hole hammer drilling are preferred in hard rock and where formation damage or lost circulation from mud is a concern; foam can be added for dust control and unstable sections.

Reverse circulation rotary uses a dual-wall pipe so cuttings return inside the inner pipe, giving cleaner, faster returns and less formation plugging in large-diameter gravel-envelope wells.

A pilot hole logged before reaming lets the driller confirm depth to target water-bearing zones and set casing and screen intervals accurately.

Casing must be plumb and centered; centralizers keep the string off the borehole wall so the annular seal is continuous rather than channeled.

Wellhead completion must include a watertight, vermin-proof cap and a sanitary seal so surface water and insects cannot enter the annular space or casing.

Well casing must be new, undamaged, and of material and wall thickness suited to the depth and load; plastic (PVC) casing carries a pressure and collapse rating that must not be exceeded by the installation depth.

The annular seal (surface seal) is placed in the space between the borehole wall and the outside of the casing, extending from land surface down to a specified minimum depth to block surface and shallow groundwater.

Sealing material must be low-permeability and must not shrink or crack: neat cement, cement-sand grout, bentonite grout, and bentonite chips/pellets are accepted; drill cuttings and native soil are not.

Tremie or positive-placement methods are required so grout is placed from the bottom up without voids, and grout is not poured from the top through standing water.

Bentonite chip seals are placed in increments and hydrated; they must be kept free of bridging and must be capped with a surface plug of grout or concrete where required.

Casing must extend at least to land surface or to a pitless adapter, and the annular seal must be continuous from the surface down to the required seal depth, not interrupted at a casing joint.

Where multiple aquifers of differing quality are penetrated, each must be isolated by casing and seal so that poor-quality water cannot migrate into a usable aquifer.

Development removes drilling fluid, fines, and filter cake from the gravel pack and screen so the well yields clear water at maximum specific capacity.

Common development methods are surging, backwashing, jetting, air-lift pumping, and overpumping; each is run until the discharge runs clear and sand content stabilizes.

Specific capacity = pumping rate divided by drawdown (gpm per foot of drawdown); a declining specific capacity over time signals plugging, screen corrosion, or declining aquifer conditions.

A pumping (aquifer) test measures drawdown versus time at a controlled rate; a step-drawdown test identifies well efficiency and the well-loss component versus aquifer loss.

Static water level is the non-pumping level; pumping water level is measured during pumping; drawdown is the difference, and both should be referenced to a stated measuring point (top of casing).

Disinfection after construction or repair typically uses a chlorine solution strong enough to give a measurable residual throughout the well, held for a contact period, then pumped to waste until the residual clears.

Water samples for bacteriological analysis are collected after disinfection is complete and chlorine has been purged, using sterile containers and aseptic technique.

Sand content, turbidity, and iron/manganese are common acceptance checks; excessive sand entry indicates development was incomplete or the screen slot size is wrong.

Abandonment must restore the borehole to a condition that prevents movement of water between aquifers and prevents surface water from entering the well or aquifer.

The standard sequence is to remove or perforate obstructions, fill the well and annular space with an approved sealing material, and seal the top with a durable cap.

Sealing material is typically neat cement or bentonite grout placed by tremie from the bottom up; the entire well bore and annular space must be filled, not just the upper portion.

Casing that cannot be removed must be perforated or ripped at intervals so the seal material can pass behind it and bond to the formation.

Where a well penetrates aquifers that must remain isolated, the seal must be placed so that each aquifer's water is confined to its own zone; the seal material must extend above the uppermost aquifer.

A well that is temporarily out of service but not abandoned must still be capped with a watertight, vermin-proof cover and kept accessible for inspection.

Abandonment is documented with a report identifying the well, method used, materials and volumes, and the sealing depths.

California well construction is governed by the Department of Water Resources bulletins (Water Well Standards) and by local county or city ordinances, which may be stricter than the state standard.

A water well driller's license (C-57) is issued by the Contractors State License Board; drilling, deepening, repairing, or abandoning a water well requires a licensed driller.

A well completion report must be filed with the Department of Water Resources for new wells, and copies go to the local enforcement agency, typically within a set period after completion.

The report documents location, dates, driller and license number, borehole and casing diameters and depths, screen or perforation intervals, seal material and depths, and water level and yield data.

Well destruction (abandonment) reports must also be filed, describing the sealing method, materials, and depths.

Property owners may drill on their own land only under the limited owner-builder exemption; it does not cover work for others or for compensation.

Local enforcement agencies (usually county environmental health) issue well permits, inspect construction, and can require stricter setbacks, seal depths, and testing than the state minimum.

The C-57 license classification covers water well drilling; a general engineering (A) or other class does not substitute for it on water well work.

Well permits are obtained from the local enforcement agency before drilling; the permit specifies allowed casing, seal depth, and setback requirements for that site.

Setback distances from contamination sources (septic systems, sewers, animal enclosures, fuel tanks) are set by local ordinance and must be met at siting, not after drilling.

The well completion report filed with DWR includes the driller's license number and signature, making the licensee accountable for the accuracy of reported depths and materials.

Failure to file required reports or drilling without a permit can result in permit denial, fines, or license discipline by the Contractors State License Board.

Continuing education and license renewal are administered by CSLB; a suspended or expired license bars the holder from contracting for well work.

Records of sealing and destruction are part of the public well record and are used by local agencies to track abandoned wells that could act as contamination pathways.

Specific capacity (gpm/ft) is computed from a stabilized pumping rate and drawdown measured after the water level has steadied.

A step-drawdown test pumps at successively higher rates and plots drawdown versus discharge to separate aquifer loss from well loss.

Disinfection contact time and chlorine residual should be verified before purging; a residual that disappears too fast suggests heavy organic load or a large water column.

Bacteriological samples must be collected after purging the chlorine and with the pump running, using sterile bottles and not overfilling.

Turbidity and sand content are measured at the discharge; persistent sand indicates an undersized screen slot or incomplete development.

Water level measurements must state the reference point (top of casing, grade) because drawdown values are meaningless without it.

Development is complete when the well produces clear, sand-free water at a stable specific capacity.

Borehole diameter must provide annular clearance for casing, centralizers, and seal; too little clearance prevents a continuous grout seal.

Cable-tool drilling uses a heavy bit lifted and dropped to fracture and loosen formation; cuttings are removed by bailing.

Mud rotary drilling circulates fluid to cool the bit, carry cuttings, and support the borehole wall; mud weight must stay between pore pressure and fracture pressure.

Air rotary and down-the-hole hammer methods are used in hard rock and where mud causes lost circulation or formation damage.

Reverse circulation returns cuttings inside a dual-wall pipe, giving cleaner samples and faster penetration in large-diameter wells.

Centralizers keep casing off the borehole wall so the annular seal forms a continuous barrier rather than a channel.

The wellhead must be completed with a watertight, vermin-proof cap and a sanitary seal to exclude surface water and insects.

Casing must be new and undamaged, with a pressure and collapse rating adequate for the installed depth; PVC casing ratings are depth-limited.

The annular surface seal extends from land surface to the required minimum depth, blocking surface water and shallow groundwater from moving down the outside of the casing.

Approved seal materials are neat cement, cement-sand grout, bentonite grout, and bentonite chips or pellets; drill cuttings and native soil are not acceptable.

Grout is placed by tremie or positive displacement from the bottom up so no voids or bridging occur and grout is not poured through standing water.

Bentonite chip seals are placed in increments and hydrated, kept free of bridging, and capped where required.

Where multiple aquifers are penetrated, casing and seal must isolate each so poor-quality water cannot migrate into a usable aquifer.

The annular seal must be continuous from the surface to the required depth and not interrupted at casing joints.

Abandonment must prevent movement of water between aquifers and prevent surface water from entering the well or aquifer.

Sequence: remove or perforate obstructions, fill the well bore and annular space with approved sealing material, and cap the top durably.

Seal material is typically neat cement or bentonite grout placed by tremie from bottom to top, filling the entire well bore and annular space.

Casing that cannot be removed must be perforated or ripped at intervals so seal material can reach the formation behind it.

Where aquifers must remain isolated, the seal must confine each aquifer's water to its own zone and extend above the uppermost aquifer.

A well temporarily out of service but not abandoned must still have a watertight, vermin-proof cap and remain accessible for inspection.

Abandonment is documented with a report identifying the well, method, materials, volumes, and sealing depths.

California water well standards are set out in DWR bulletins, and local county or city ordinances may impose stricter requirements.

A C-57 water well driller's license from the Contractors State License Board is required to drill, deepen, repair, or abandon a water well.

A well completion report must be filed with DWR for new wells, with copies to the local enforcement agency, documenting construction details.

The report includes location, dates, driller and license number, borehole and casing diameters and depths, screen intervals, seal materials and depths, and water level and yield data.

Well destruction reports must also be filed, describing sealing method, materials, and depths.

The owner-builder exemption allows a property owner to drill on their own land only, not for others or for compensation.

Local enforcement agencies issue well permits, inspect construction, and may require stricter setbacks, seal depths, and testing than the state minimum.

Development removes drilling fluid, fines, and filter cake from the gravel pack and screen until the well yields clear water at maximum specific capacity.

Development methods include surging, backwashing, jetting, air-lift pumping, and overpumping, run until discharge is clear and sand content stabilizes.

Specific capacity equals pumping rate divided by drawdown, in gpm per foot; declining specific capacity indicates plugging or aquifer decline.

A pumping test measures drawdown versus time at a controlled rate; a step-drawdown test separates aquifer loss from well loss.

Static water level is the non-pumping level, pumping level is measured during pumping, and drawdown is the difference, referenced to a stated measuring point.

Disinfection after construction or repair uses a chlorine solution with a measurable residual, held for a contact period, then purged to waste.

Bacteriological samples are collected after chlorine is purged, using sterile containers and aseptic technique with the pump running.

Annular clearance of at least about 2 in (5 cm) on each side of the casing is a common working rule for a proper seal and gravel envelope.

Cable-tool drilling suits unconsolidated alluvium and boulder-bearing formations but is slow in hard rock; samples are bailed.

Mud rotary drilling circulates fluid to cool the bit, lift cuttings, and hold the borehole open; mud weight must exceed pore pressure but stay below fracture pressure.

Air rotary and down-the-hole hammer drilling are preferred in hard rock and where mud causes lost circulation or formation damage.

Reverse circulation uses a dual-wall pipe so cuttings return inside the inner pipe, giving cleaner returns and less plugging in large-diameter wells.

A pilot hole logged before reaming confirms depth to water-bearing zones and guides casing and screen placement.

Centralizers keep the casing string off the borehole wall so the annular seal is continuous rather than channeled.

Well casing must be new, undamaged, and rated for the installed depth; PVC casing has pressure and collapse limits that must not be exceeded.

The annular surface seal blocks surface water and shallow groundwater from moving down the outside of the casing.

Approved seal materials are neat cement, cement-sand grout, bentonite grout, and bentonite chips or pellets; cuttings and native soil are not acceptable.

Grout must be placed by tremie or positive displacement from the bottom up to avoid voids and bridging.

Bentonite chip seals are placed in increments and hydrated, kept free of bridging, and capped where required.

Where multiple aquifers are penetrated, each must be isolated by casing and seal so poor-quality water cannot migrate into a usable aquifer.

The annular seal must be continuous from land surface to the required depth and not interrupted at casing joints.

Abandonment must restore the borehole so water cannot move between aquifers and surface water cannot enter the well or aquifer.

Standard sequence: remove or perforate obstructions, fill the well and annular space with approved sealing material, and seal the top with a durable cap.

Sealing material is typically neat cement or bentonite grout placed by tremie from the bottom up, filling the entire well bore and annular space.

Casing that cannot be removed must be perforated or ripped at intervals so seal material can pass behind it and bond to the formation.

Where aquifers must remain isolated, the seal must confine each aquifer's water to its own zone and extend above the uppermost aquifer.

A well temporarily out of service but not abandoned must still be capped with a watertight, vermin-proof cover and kept accessible for inspection.

Abandonment is documented with a report identifying the well, method used, materials and volumes, and sealing depths.

California well construction is governed by DWR water well standards bulletins and by local county or city ordinances, which may be stricter.

A C-57 water well driller's license from the Contractors State License Board is required to drill, deepen, repair, or abandon a water well.

A well completion report must be filed with DWR for new wells, with copies to the local enforcement agency, within the required period after completion.

The report documents location, dates, driller and license number, borehole and casing diameters and depths, screen intervals, seal materials and depths, and water level and yield data.

Well destruction reports must also be filed, describing sealing method, materials, and depths.

The owner-builder exemption allows a property owner to drill on their own land only; it does not cover work for others or for compensation.

Local enforcement agencies issue well permits, inspect construction, and may require stricter setbacks, seal depths, and testing than the state minimum.

Development removes drilling fluid, fines, and filter cake from the gravel pack and screen until the well yields clear water at maximum specific capacity.

Development methods include surging, backwashing, jetting, air-lift pumping, and overpumping, run until discharge is clear and sand content stabilizes.

Specific capacity equals pumping rate divided by drawdown, in gpm per foot; declining specific capacity signals plugging, screen corrosion, or aquifer decline.

A pumping test measures drawdown versus time at a controlled rate; a step-drawdown test separates aquifer loss from well loss.

Static water level is the non-pumping level, pumping level is measured during pumping, and drawdown is the difference, referenced to a stated measuring point.

Disinfection after construction or repair uses a chlorine solution with a measurable residual, held for a contact period, then purged to waste.

Bacteriological samples are collected after chlorine is purged, using sterile containers and aseptic technique with the pump running.

Borehole diameter must leave annular clearance for casing, centralizers, and seal; too little clearance prevents a continuous grout seal.

Cable-tool drilling uses a heavy bit lifted and dropped to fracture and loosen formation; cuttings are removed by bailing.

Mud rotary drilling circulates fluid to cool the bit, carry cuttings, and support the borehole wall; mud weight must stay between pore pressure and fracture pressure.

Air rotary and down-the-hole hammer methods are used in hard rock and where mud causes lost circulation or formation damage.

Reverse circulation returns cuttings inside a dual-wall pipe, giving cleaner samples and faster penetration in large-diameter wells.

Centralizers keep casing off the borehole wall so the annular seal forms a continuous barrier rather than a channel.

The wellhead must be completed with a watertight, vermin-proof cap and a sanitary seal to exclude surface water and insects.

Casing must be new and undamaged, with a pressure and collapse rating adequate for the installed depth; PVC casing ratings are depth-limited.

The annular surface seal extends from land surface to the required minimum depth, blocking surface water and shallow groundwater from moving down the outside of the casing.

Approved seal materials are neat cement, cement-sand grout, bentonite grout, and bentonite chips or pellets; drill cuttings and native soil are not acceptable.

Grout is placed by tremie or positive displacement from the bottom up so no voids or bridging occur and grout is not poured through standing water.

Bentonite chip seals are placed in increments and hydrated, kept free of bridging, and capped where required.

Where multiple aquifers are penetrated, casing and seal must isolate each so poor-quality water cannot migrate into a usable aquifer.

The annular seal must be continuous from the surface to the required depth and not interrupted at casing joints.

Abandonment must prevent movement of water between aquifers and prevent surface water from entering the well or aquifer.

Sequence: remove or perforate obstructions, fill the well bore and annular space with approved sealing material, and cap the top durably.

Seal material is typically neat cement or bentonite grout placed by tremie from bottom to top, filling the entire well bore and annular space.

Casing that cannot be removed must be perforated or ripped at intervals so seal material can reach the formation behind it.

Where aquifers must remain isolated, the seal must confine each aquifer's water to its own zone and extend above the uppermost aquifer.

A well temporarily out of service but not abandoned must still have a watertight, vermin-proof cap and remain accessible for inspection.

Abandonment is documented with a report identifying the well, method, materials, volumes, and sealing depths.

California water well standards are set out in DWR bulletins, and local county or city ordinances may impose stricter requirements.

A C-57 water well driller's license from the Contractors State License Board is required to drill, deepen, repair, or abandon a water well.

A well completion report must be filed with DWR for new wells, with copies to the local enforcement agency, documenting construction details.

The report includes location, dates, driller and license number, borehole and casing diameters and depths, screen intervals, seal materials and depths, and water level and yield data.

Well destruction reports must also be filed, describing sealing method, materials, and depths.

The owner-builder exemption allows a property owner to drill on their own land only, not for others or for compensation.

Local enforcement agencies issue well permits, inspect construction, and may require stricter setbacks, seal depths, and testing than the state minimum.

Development removes drilling fluid, fines, and filter cake from the gravel pack and screen until the well yields clear water at maximum specific capacity.

Development methods include surging, backwashing, jetting, air-lift pumping, and overpumping, run until discharge is clear and sand content stabilizes.

Specific capacity equals pumping rate divided by drawdown, in gpm per foot; declining specific capacity indicates plugging or aquifer decline.

A pumping test measures drawdown versus time at a controlled rate; a step-drawdown test separates aquifer loss from well loss.

Static water level is the non-pumping level, pumping level is measured during pumping, and drawdown is the difference, referenced to a stated measuring point.

Disinfection after construction or repair uses a chlorine solution with a measurable residual, held for a contact period, then purged to waste.

Bacteriological samples are collected after chlorine is purged, using sterile containers and aseptic technique with the pump running.

Annular clearance of at least about 2 in (5 cm) on each side of the casing is a common working rule for a proper seal and gravel envelope.

Cable-tool drilling suits unconsolidated alluvium and boulder-bearing formations but is slow in hard rock; samples are bailed.

Mud rotary drilling circulates fluid to cool the bit, lift cuttings, and hold the borehole open; mud weight must exceed pore pressure but stay below fracture pressure.

Air rotary and down-the-hole hammer drilling are preferred in hard rock and where mud causes lost circulation or formation damage.

Reverse circulation uses a dual-wall pipe so cuttings return inside the inner pipe, giving cleaner returns and less plugging in large-diameter wells.

A pilot hole logged before reaming confirms depth to water-bearing zones and guides casing and screen placement.

Centralizers keep the casing string off the borehole wall so the annular seal is continuous rather than channeled.

Well casing must be new, undamaged, and rated for the installed depth; PVC casing has pressure and collapse limits that must not be exceeded.

The annular surface seal blocks surface water and shallow groundwater from moving down the outside of the casing.

Approved seal materials are neat cement, cement-sand grout, bentonite grout, and bentonite chips or pellets; cuttings and native soil are not acceptable.

Grout must be placed by tremie or positive displacement from the bottom up to avoid voids and bridging.

Bentonite chip seals are placed in increments and hydrated, kept free of bridging, and capped where required.

Where multiple aquifers are penetrated, each must be isolated by casing and seal so poor-quality water cannot migrate into a usable aquifer.

The annular seal must be continuous from land surface to the required depth and not interrupted at casing joints.

Abandonment must restore the borehole so water cannot move between aquifers and surface water cannot enter the well or aquifer.

Standard sequence: remove or perforate obstructions, fill the well and annular space with approved sealing material, and seal the top with a durable cap.

Sealing material is typically neat cement or bentonite grout placed by tremie from the bottom up, filling the entire well bore and annular space.

Casing that cannot be removed must be perforated or ripped at intervals so seal material can pass behind it and bond to the formation.

Where aquifers must remain isolated, the seal must confine each aquifer's water to its own zone and extend above the uppermost aquifer.

A well temporarily out of service but not abandoned must still be capped with a watertight, vermin-proof cover and kept accessible for inspection.

Abandonment is documented with a report identifying the well, method used, materials and volumes, and sealing depths.

California well construction is governed by DWR water well standards bulletins and by local county or city ordinances, which may be stricter.

A C-57 water well driller's license from the Contractors State License Board is required to drill, deepen, repair, or abandon a water well.

A well completion report must be filed with DWR for new wells, with copies to the local enforcement agency, within the required period after completion.

The report documents location, dates, driller and license number, borehole and casing diameters and depths, screen intervals, seal materials and depths, and water level and yield data.

Well destruction reports must also be filed, describing sealing method, materials, and depths.

The owner-builder exemption allows a property owner to drill on their own land only; it does not cover work for others or for compensation.

Local enforcement agencies issue well permits, inspect construction, and may require stricter setbacks, seal depths, and testing than the state minimum.

Development removes drilling fluid, fines, and filter cake from the gravel pack and screen until the well yields clear water at maximum specific capacity.

Development methods include surging, backwashing, jetting, air-lift pumping, and overpumping, run until discharge is clear and sand content stabilizes.

Specific capacity equals pumping rate divided by drawdown, in gpm per foot; declining specific capacity signals plugging, screen corrosion, or aquifer decline.

A pumping test measures drawdown versus time at a controlled rate; a step-drawdown test separates aquifer loss from well loss.

Static water level is the non-pumping level, pumping level is measured during pumping, and drawdown is the difference, referenced to a stated measuring point.

Disinfection after construction or repair uses a chlorine solution with a measurable residual, held for a contact period, then purged to waste.

Bacteriological samples are collected after chlorine is purged, using sterile containers and aseptic technique with the pump running.

Borehole diameter must leave annular clearance for casing, centralizers, and seal; too little clearance prevents a continuous grout seal.

Cable-tool drilling uses a heavy bit lifted and dropped to fracture and loosen formation; cuttings are removed by bailing.

Mud rotary drilling circulates fluid to cool the bit, carry cuttings, and support the borehole wall; mud weight must stay between pore pressure and fracture pressure.

Air rotary and down-the-hole hammer methods are used in hard rock and where mud causes lost circulation or formation damage.

Reverse circulation returns cuttings inside a dual-wall pipe, giving cleaner samples and faster penetration in large-diameter wells.

Centralizers keep casing off the borehole wall so the annular seal forms a continuous barrier rather than a channel.

The wellhead must be completed with a watertight, vermin-proof cap and a sanitary seal to exclude surface water and insects.

Casing must be new and undamaged, with a pressure and collapse rating adequate for the installed depth; PVC casing ratings are depth-limited.

The annular surface seal extends from land surface to the required minimum depth, blocking surface water and shallow groundwater from moving down the outside of the casing.

Approved seal materials are neat cement, cement-sand grout, bentonite grout, and bentonite chips or pellets; drill cuttings and native soil are not acceptable.

Grout is placed by tremie or positive displacement from the bottom up so no voids or bridging occur and grout is not poured through standing water.

Bentonite chip seals are placed in increments and hydrated, kept free of bridging, and capped where required.

Where multiple aquifers are penetrated, casing and seal must isolate each so poor-quality water cannot migrate into a usable aquifer.

The annular seal must be continuous from the surface to the required depth and not interrupted at casing joints.

Abandonment must prevent movement of water between aquifers and prevent surface water from entering the well or aquifer.

Sequence: remove or perforate obstructions, fill the well bore and annular space with approved sealing material, and cap the top durably.

Seal material is typically neat cement or bentonite grout placed by tremie from bottom to top, filling the entire well bore and annular space.

Casing that cannot be removed must be perforated or ripped at intervals so seal material can reach the formation behind it.

Where aquifers must remain isolated, the seal must confine each aquifer's water to its own zone and extend above the uppermost aquifer.

A well temporarily out of service but not abandoned must still have a watertight, vermin-proof cap and remain accessible for inspection.

Abandonment is documented with a report identifying the well, method, materials, volumes, and sealing depths.

California water well standards are set out in DWR bulletins, and local county or city ordinances may impose stricter requirements.

A C-57 water well driller's license from the Contractors State License Board is required to drill, deepen, repair, or abandon a water well.

A well completion report must be filed with DWR for new wells, with copies to the local enforcement agency, documenting construction details.

The report includes location, dates, driller and license number, borehole and casing diameters and depths, screen intervals, seal materials and depths, and water level and yield data.

Well destruction reports must also be filed, describing sealing method, materials, and depths.

The owner-builder exemption allows a property owner to drill on their own land only, not for others or for compensation.

Local enforcement agencies issue well permits, inspect construction, and may require stricter setbacks, seal depths, and testing than the state minimum.

Development removes drilling fluid, fines, and filter cake from the gravel pack and screen until the well yields clear water at maximum specific capacity.

Development methods include surging, backwashing, jetting, air-lift pumping, and overpumping, run until discharge is clear and sand content stabilizes.

Specific capacity equals pumping rate divided by drawdown, in gpm per foot; declining specific capacity indicates plugging or aquifer decline.

A pumping test measures drawdown versus time at a controlled rate; a step-drawdown test separates aquifer loss from well loss.

Static water level is the non-pumping level, pumping level is measured during pumping, and drawdown is the difference, referenced to a stated measuring point.

Disinfection after construction or repair uses a chlorine solution with a measurable residual, held for a contact period, then purged to waste.

Bacteriological samples are collected after chlorine is purged, using sterile containers and aseptic technique with the pump running.