MI Well Driller cheat sheet

Setback rule of thumb for a new well: locate as far as practical and upgradient from septic systems, barnyards, fuel storage, and road salt storage; separation distances are measured horizontally from the wellhead to the nearest edge of the pollution source.

Michigan glacial geology controls yield: outwash sand and gravel and esker/kame deposits give the highest specific capacity; till and lacustrine clay give low yields and perched water; bedrock aquifers (Marshall, Saginaw, Traverse) vary widely by fracture density.

Confined aquifers sit beneath a low-permeability confining layer (clay till, shale) and produce artesian rise; unconfined aquifers respond quickly to precipitation and are more vulnerable to surface contamination.

Static water level is measured before pumping; pumping water level is measured during stabilized pumping; drawdown = pumping level minus static level.

Specific capacity = pumping rate (gpm) divided by drawdown (ft); a declining specific capacity over years signals plugging, encrustation, or regional decline.

A well sited in a floodplain must have the casing extended and the wellhead sealed so that floodwater cannot enter; finished grade must drain away from the wellhead.

Test-hole logs (driller's log of depth, material, and water strikes) are the primary siting tool; a nearby log is not a substitute for a test hole on the parcel.

Karst and fractured-bedrock settings require extra casing depth to seal off solution openings and shallow fracture zones that transmit surface water.

Casing must extend from the wellhead to a depth that seals off unconsolidated material and shallow contaminated water and reaches competent, low-permeability formation or bedrock.

Annular space must be large enough to place a tremie pipe and grout column; typical minimum is 2 in of annular clearance, and larger holes are needed for deep grout placement.

Well screen slot size is selected to retain the formation: use a sieve analysis of the aquifer sample; slot openings are commonly sized to pass 40-50% of the formation material.

A gravel pack is placed where the formation is fine or uniform; the pack grain size is typically 4-6 times the formation D50, and the screen slot retains the pack.

Centralizers keep the casing centered in the borehole so the grout seal has uniform thickness on all sides.

The wellhead must terminate above grade (commonly at least 12 in, and higher in flood-prone areas) with a sanitary, vermin-proof cap and a grout seal at the surface.

Drive shoe on the bottom of the casing protects the casing and provides a seal as it is driven into firm material.

Plumbness and alignment checks are made before setting the pump; excessive deviation can prevent pump installation and damage the pump assembly.

Neat cement grout is mixed at no more than 6 gallons of water per 94-lb sack of cement; bentonite-based grout is mixed per the manufacturer's ratio, and extra water weakens the seal and causes shrinkage.

Place grout by the tremie method from the bottom of the annular space upward so the grout displaces drilling fluid and does not bridge or channel.

Grout volume estimate: annular volume = 0.7854 x (hole diameter squared minus casing OD squared) x height; add 10-25% for lost circulation and washouts.

Bentonite grout shrinks slightly on curing and can crack; cement-bentonite or neat cement is preferred where a permanent, low-permeability seal is required.

Never grout through a casing that is full of drilling fluid without a tremie; dropping grout from the top causes segregation and voids.

Surface seal: a grout collar at the wellhead, typically at least 2 in thick and extending outward, sheds surface water and prevents annular entry.

Grouting a well that penetrates multiple aquifers must seal the annulus over the full length of casing so that aquifers are not cross-connected.

Verify grout returns at the surface where possible; missing returns indicate loss to a void or fracture and require additional grout.

Development removes drilling fluid, fines, and filter cake; methods include surging, jetting, air-lifting, and overpumping, and are continued until discharge runs clear.

Development is done before the pump is set and before the final disinfection; overpumping during development must not exceed the screen's collapse strength.

Pump setting depth must keep the pump submerged below the pumping water level by the manufacturer's minimum submergence (often 10-20 ft) to avoid cavitation and overheating.

Submersible pump sizing: match the pump curve to the well yield so the operating point falls in the efficient range and does not draw the well down below the pump intake.

Drop pipe, torque arrestor, and check valve installation: a check valve above the pump holds the column of water and prevents backspin on shutdown.

Pump capacity in gpm and total dynamic head (TDH) in ft determine motor horsepower; TDH = pumping lift + discharge head + friction losses.

Sanitary well cap and vented, screened vent allow air movement while keeping insects and surface water out; the conduit to the pitless adapter must be watertight.

Pitless adapter allows the discharge line to pass through the casing below frost depth while keeping the wellhead sealed.

Sample before any treatment or softener, and preferably before the pressure tank, from a clean, disinfected sampling point; do not sample through a hose or an aerator.

Bacteriological sampling: use a sterile bottle with sodium thiosulfate, fill to the line, leave air space, chill, and submit within the holding time (commonly 24-30 hours).

Coliform presence indicates a pathway for surface contamination; E. coli presence indicates fecal contamination and requires investigation, disinfection, and retesting.

Common Michigan groundwater concerns: arsenic (especially in some bedrock and outwash areas), nitrate from septic and agriculture, iron and manganese staining, hardness, and radon.

Nitrate above 10 mg/L as N is the drinking-water standard; nitrate in a well often signals a failing septic system or fertilizer influence nearby.

Shock chlorination: calculate volume of water in the well and plumbing, add chlorine to reach roughly 50-200 mg/L, circulate, hold, then flush until chlorine is gone and retest.

Field meters need calibration before each sampling day; pH, temperature, and specific conductance are measured in a flow cell or in a clean container at the wellhead.

Chain of custody and proper labeling (site, date, time, sampler, analysis requested) are required for a defensible water-quality result.

Abandonment is required when a well is no longer used, is unsafe, or cannot be repaired; a well that is not properly plugged is a direct pathway for contamination into the aquifer.

Remove the pump, drop pipe, and any obstructions first; then fill the well from the bottom up with an approved plugging material.

Approved plugging materials include neat cement grout, cement-bentonite, bentonite chips or pellets, and sand or gravel only where specified for the lower portion below the seal.

Placement by tremie is required so the material fills the full column without bridging; free-falling material can leave voids and channels.

Casing should be cut off below grade (commonly at least 3 ft below ground surface) and the remaining hole filled and capped so the site drains and the location is not a hazard.

A plugged well must be documented: depth, diameter, materials used, volumes, date, and method, and the record provided to the owner and the state.

Flowing artesian wells require a plugging material that sets under pressure and a seal deep enough to control the flow before the upper casing is cut.

Abandoned wells that penetrate multiple aquifers must be sealed across each aquifer so that cross-connection between aquifers does not occur.

Michigan regulates water well construction under the state's water well statute and administrative rules; a driller must hold the appropriate state-issued well drilling credential to construct, alter, or plug a well.

A well record (driller's log) must be completed for each well and filed with the state within the required time, listing depth, casing, screen, grout, and water-bearing zones.

Casing and grout requirements set minimum depths and wall thicknesses; the casing must be new, sound, and free of joints that leak.

Wells must be disinfected after construction and before being placed in service; a bacteriological sample is collected after disinfection clears.

Setbacks from sources of contamination (septic systems, sewers, fuel tanks, animal lots) are specified in rule and measured from the wellhead.

Plugging of abandoned wells must follow the state's approved methods and materials; a plugging record is filed with the state.

Changes to a well (deepening, re-casing, pump replacement that opens the seal) may require a permit or notification; check the local health department and state requirements before work.

Local health departments may impose additional requirements, so verify local rules in addition to state rules before siting or constructing.

Before drilling, call 811 for utility locates and wait the required notice period; never assume a line is absent because the area looks clear.

Confined space entry (pit, vault, large-diameter well) requires air monitoring for oxygen and toxic gases, a permit, an attendant, and retrieval equipment.

Rigging and hoisting: know the load rating of cables, slings, and the derrick; keep personnel out from under suspended loads and never ride the traveling block.

Rotating equipment hazards: no loose clothing, jewelry, or long hair near the rotary table; lock out and tag out before servicing the rig or pump.

Electrical safety around submersible pumps: de-energize and verify at the panel before pulling a pump; use GFCI protection on jobsite circuits.

Silica dust from drilling and cutting is a respiratory hazard; use water or dust suppression and wear appropriate respiratory protection.

Chemical handling: store and mix grout, chlorine, and drilling fluids per the SDS; provide eye wash and spill containment, and keep chlorine away from acids.

Heat and cold stress, hearing protection near the rig, and a stocked first-aid kit are standard jobsite requirements; know the emergency address for the 911 call.