LA Plumber cheat sheet

In Louisiana, plumbing work is regulated under the state Uniform Construction Code; the Louisiana State Plumbing Board licenses journeyman and master plumbers, while local parishes and municipalities issue permits and inspect.

A permit is required before installing, altering, or replacing any plumbing system or fixture, and before cutting structural members; ordinary repairs and stoppage clearing do not require a permit.

Permits expire if work does not commence within 180 days of issuance or if work is suspended for 180 days; a new permit and fee are required afterward.

Inspections must be requested at required stages: underground/rough-in before concealment, and final after fixtures and testing are complete; concealed work may not be covered before rough-in approval.

The code official may order work stopped via a stop-work order for unpermitted or unsafe work; work may not resume until the order is lifted.

Where the code is silent, the adopted plumbing code (IAPMO Uniform Plumbing Code as amended by the state) governs; local amendments take precedence over the model code.

A master plumber is responsible for the work of journeymen and apprentices under their employ; apprentices may not work unsupervised on gas or medical gas systems.

Violations are corrected at the owner's expense; failure to comply can result in permit revocation, fines, and utility service disconnection.

Fixture units (FU) convert dissimilar fixtures to a common load basis: a water closet = 3 FU (drainage), a lavatory = 1 FU, a bathtub = 2 FU, a floor drain = 1-4 FU depending on size.

Total drainage fixture units (DFU) in a building determine the required building drain and building sewer size via the code sizing table (e.g., 4-inch building drain carries up to 216 DFU).

Total water supply fixture units (WSFU) are converted to probable demand in gallons per minute using the Hunter curve or equivalent table; demand is not the sum of fixture flow rates.

Slope and capacity: 1/4 inch per foot (2%) for pipe 2.5 inches and smaller, 1/8 inch per foot (1%) for 3-inch and larger; capacity decreases as slope decreases.

Fall in inches = slope (in/ft) x run (ft). Example: 60 ft at 1/4 in/ft = 15 inches of fall.

Pipe volume in gallons = 0.7854 x (inside diameter in inches)^2 x length in feet / 231.

Developed length = horizontal run + vertical rise + fitting allowances; add equivalent lengths for elbows, tees, and valves from the fitting table before sizing.

Static pressure at a fixture = supply pressure - (elevation gain in feet x 0.433 psi/ft) - friction loss; 1 psi = 2.31 feet of head.

Minimum residual pressure: 8 psi at a flush-valve water closet, 15 psi at a flushometer valve bank, and 8 psi at a sill cock, measured at the fixture during peak demand.

Approved potable water piping includes copper (Type L or K), PEX, CPVC, galvanized steel, and stainless steel; lead pipe, lead solder, and leaded brass are prohibited for potable water.

Copper joints are brazed or soldered with lead-free solder (maximum 0.2% lead); PEX uses ASTM F1807 or F1960 fittings and must be protected from UV light and physical damage.

Water supply pipe must be supported at intervals per material: copper horizontal 6 ft (1-1/4 in and smaller), PEX horizontal 32 in, CPVC horizontal 3 ft.

Buried water service must have at least 12 inches of cover below the frost line or be installed per the local depth requirement; in Louisiana, 18-24 inches is typical for service lines.

Water service must be tested at working pressure or 50 psi (whichever is greater) for at least 60 minutes with no drop in pressure; air testing is not permitted for plastic water pipe.

A full-open valve is required on the building side of the meter; a main shutoff and drain valve must be accessible.

Hot and cold water piping must be insulated where exposed to freezing or where required for energy conservation; hot and cold lines must be separated by at least 6 inches in the same trench.

Water hammer arrestors are required at quick-closing valves (flushometers, solenoid valves) and at the end of long runs.

Drainage pipe slope: 1/4 in/ft for 2 in and smaller, 1/8 in/ft for 3 in and larger; horizontal drainage pipe must be supported at 4 ft intervals for cast iron and 4 ft for plastic (with 10 ft maximum spacing for larger sizes).

A trap must be installed for every fixture except those with integral traps; trap seal depth is 2-4 inches, and each trap must be vented.

Vent stack must extend at least 6 inches above the roof or 12 inches above a roof used for other purposes; the vent terminal must be at least 10 ft from any window, door, or air intake.

A vent must be at least 6 inches above the flood-level rim of the highest fixture served, and a horizontal vent must slope back to the drain at 1/4 in/ft.

Wet venting is prohibited for water closets and for fixtures on different floors; a wet vent may serve only fixtures on the same floor and must be sized per the table.

A cleanout is required at the base of each stack, at the building drain, at changes in direction greater than 45 degrees, and at intervals not exceeding 100 ft in horizontal drains.

A backwater valve is required where the building drain is below the level of the public sewer or where the sewer may surcharge; it must be accessible for maintenance.

The building drain extends from the building to the building sewer, and the building sewer extends from the building drain to the public sewer or private disposal system.

Water closets must be installed with a 4-inch drain, 12-inch rough-in from finished wall to closet bolt center (typical), and a water supply with a stop valve; the flange must be secured to the floor.

Fixture water supply: lavatories 3/8 in, water closets 3/8 in (tank type) or 1 in (flushometer), bathtubs 1/2 in, and sill cocks 1/2 in.

A lavatory must have a 1-1/4 inch trap and drain; a water closet uses a 3-inch or 4-inch closet bend; a bathtub uses a 1-1/2 inch drain.

Floor drains must have a trap with a minimum 2-inch seal and be provided with a strainer; trap primers are required where the trap may evaporate.

A dishwasher must have an air gap or high-loop drain connection to prevent backflow; the discharge must connect to the sink drain or a separate trap.

A clothes washer requires a 2-inch standpipe with a trap and a 2-inch vent; the standpipe must be at least 18 inches and not more than 42 inches above the floor.

A water heater must be installed with a temperature and pressure relief valve, a discharge pipe terminating within 6 inches of the floor, and a drain pan where leakage could cause damage.

Fixture clearances: a water closet requires at least 15 inches from centerline to side wall and 21 inches in front of the bowl; a lavatory requires 15 inches centerline to side wall.

A temperature and pressure relief valve is required on every water heater; its discharge pipe must be full size, terminate within 6 inches of the floor, and not be trapped or reduced.

A water heater must have a shutoff valve on the cold water inlet and a union or flange for removal; the T&P valve must be piped to a safe location.

Gas piping must be sized per the longest length method or branch length method using the tables; pressure drop is limited to 0.5 in w.c. for natural gas at low pressure.

Gas pipe must be supported at 6 ft intervals and protected from physical damage; a sediment trap is required at the appliance connection.

Gas piping must be tested with air or inert gas at 10 psi for at least 30 minutes for systems up to 125 psi working pressure; the test must be witnessed by the code official.

A gas shutoff valve must be installed within 6 ft of the appliance and in the same room; a union must be installed downstream of the shutoff valve.

Flue and vent connectors must have a minimum 6-inch rise before any offset, and a draft hood must be installed per the appliance listing.

A water heater in a garage must be elevated so the ignition source is at least 18 inches above the floor unless listed as flammable-vapor ignition resistant.

The building sewer must be sized by the total DFU; minimum size is 4 inches for a building sewer serving a building with water closets, and 3 inches for a building with no water closets.

Sewer pipe must be laid on a uniform grade with a minimum slope of 1/4 in/ft for 4-inch pipe and 1/8 in/ft for 6-inch pipe; the invert must be at least 2 ft below the building drain.

A sewer cleanout is required at the property line, at the building sewer, and at intervals not exceeding 100 ft; cleanouts must be accessible and have a gas-tight cover.

Storm drainage must be separate from sanitary drainage; roof drains and area drains must discharge to a storm sewer or approved disposal system, not the sanitary sewer.

Roof drain sizing depends on the roof area, rainfall intensity (inches per hour), and the drain size; the 100-year, 1-hour rainfall intensity for the local area is used.

Storm drain pipe must be sized for the design flow and slope; the minimum size is 3 inches and the minimum slope is 1/4 in/ft for 3-inch pipe.

A backwater valve is required on the building sewer where the building drain is below the level of the public sewer or where the sewer may surcharge.

Sewer joints must be watertight and root-resistant; clay tile, cast iron, PVC, and ductile iron are common materials, and the pipe must be bedded per the manufacturer's instructions.

A cross-connection is any actual or potential connection between the potable water system and a source of contamination; it must be eliminated or protected by an approved backflow preventer.

An air gap is the only absolute protection against backflow; it must be at least twice the diameter of the supply pipe and never less than 1 inch above the flood-level rim.

A reduced pressure zone (RPZ) assembly is required for high-hazard connections (e.g., boiler feed, chemical injection, irrigation with fertilizer); it must be tested annually by a certified tester.

A double check valve assembly is used for low-hazard connections and must be tested annually; a pressure vacuum breaker is used for lawn irrigation and must be installed 12 inches above the highest downstream outlet.

A hose bibb vacuum breaker is required on all sill cocks and hose connections; it must be listed and must not be removed.

Backflow preventers must be installed in an accessible location, protected from freezing, and not installed below grade unless in a vault with drainage.

The potable water system must be protected from contamination during construction by caps and plugs; a final disinfection with chlorine (50 ppm for 24 hours or 200 ppm for 3 hours) is required for new mains.

A plumbing permit is required to install or replace a backflow preventer, and the assembly must be inspected and tested after installation.

Personal protective equipment: safety glasses with side shields, gloves, hard hat, and steel-toe boots are required on construction sites; hearing protection is required when noise exceeds 85 dBA.

Confined spaces (excavations deeper than 4 ft, tanks, vaults) require atmospheric testing for oxygen, flammable gas, and hydrogen sulfide before entry and continuous monitoring during entry.

Trench protection: any excavation 5 ft or deeper requires a protective system (sloping, shoring, or trench box); spoil piles must be kept at least 2 ft from the edge.

Before digging, call 811 to locate underground utilities and wait the required time (typically 48 hours in Louisiana); hand-dig within 24 inches of marked utilities.

Soldering copper requires a fire watch and a fire extinguisher; remove or protect combustible materials within 18 inches of the work area.

A pipe wrench is sized by the pipe diameter it fits; use a backing wrench on the opposite side of a fitting to prevent damage to the pipe or valve.

A hydrostatic test is the standard for DWV systems: fill the system with water to at least 10 ft of head above the highest fitting and hold for 15 minutes before inspection.

Lockout/tagout procedures must be followed before servicing gas or electrical equipment; verify the energy source is isolated and tagged before work begins.

Copper tube types: K (thickest, underground), L (standard, most common), M (thin wall, aboveground only); type M is not permitted underground.

PEX tubing must be protected from sunlight and must not be installed within 12 inches of a heat source; it must be supported per the manufacturer's instructions and tested with water.

Water piping must be tested at 50 psi or working pressure, whichever is greater, for at least 60 minutes; the test must be witnessed by the code official.

A water service must have a main shutoff valve, a meter, and a pressure-reducing valve if the supply pressure exceeds 80 psi.

Hot water piping must be insulated where required by the energy code; cold water piping must be insulated where it may sweat or freeze.

A water hammer arrestor must be installed at the end of a long run and at quick-closing valves; it must be accessible for maintenance.

Backflow prevention is required at the water service connection if a boiler, irrigation system, or chemical injection is connected.

Pipe hangers and supports must be listed and sized for the pipe; plastic pipe must be supported with hangers that do not damage the pipe.

A water closet must be installed with a 4-inch drain and a water supply with a stop valve; the flange must be secured to the floor and the closet must be level.

A lavatory must have a 1-1/4 inch trap and drain; a bathtub must have a 1-1/2 inch drain; a water closet must have a 3-inch or 4-inch closet bend.

A floor drain must have a trap with a minimum 2-inch seal and a strainer; a trap primer is required where the trap may evaporate.

A dishwasher must have an air gap or high-loop drain connection to prevent backflow; the discharge must connect to the sink drain or a separate trap.

A clothes washer requires a 2-inch standpipe with a trap and a 2-inch vent; the standpipe must be at least 18 inches and not more than 42 inches above the floor.

A water heater must be installed with a temperature and pressure relief valve, a discharge pipe terminating within 6 inches of the floor, and a drain pan where leakage could cause damage.

Fixture clearances: a water closet requires at least 15 inches from centerline to side wall and 21 inches in front of the bowl; a lavatory requires 15 inches centerline to side wall.

A fixture must be installed with a water supply and a drain; the fixture must be accessible for cleaning and repair, and the trap must be accessible.

A temperature and pressure relief valve is required on every water heater; its discharge pipe must be full size, terminate within 6 inches of the floor, and not be trapped or reduced.

A water heater must have a shutoff valve on the cold water inlet and a union or flange for removal; the T&P valve must be piped to a safe location.

Gas piping must be sized per the longest length method or branch length method using the tables; pressure drop is limited to 0.5 in w.c. for natural gas at low pressure.

Gas pipe must be supported at 6 ft intervals and protected from physical damage; a sediment trap is required at the appliance connection.

Gas piping must be tested with air or inert gas at 10 psi for at least 30 minutes for systems up to 125 psi working pressure; the test must be witnessed by the code official.

A gas shutoff valve must be installed within 6 ft of the appliance and in the same room; a union must be installed downstream of the shutoff valve.

Flue and vent connectors must have a minimum 6-inch rise before any offset, and a draft hood must be installed per the appliance listing.

A water heater in a garage must be elevated so the ignition source is at least 18 inches above the floor unless listed as flammable-vapor ignition resistant.

The building sewer must be sized by the total DFU; minimum size is 4 inches for a building sewer serving a building with water closets, and 3 inches for a building with no water closets.

Sewer pipe must be laid on a uniform grade with a minimum slope of 1/4 in/ft for 4-inch pipe and 1/8 in/ft for 6-inch pipe; the invert must be at least 2 ft below the building drain.

A sewer cleanout is required at the property line, at the building sewer, and at intervals not exceeding 100 ft; cleanouts must be accessible and have a gas-tight cover.

Storm drainage must be separate from sanitary drainage; roof drains and area drains must discharge to a storm sewer or approved disposal system, not the sanitary sewer.

Roof drain sizing depends on the roof area, rainfall intensity (inches per hour), and the drain size; the 100-year, 1-hour rainfall intensity for the local area is used.

Storm drain pipe must be sized for the design flow and slope; the minimum size is 3 inches and the minimum slope is 1/4 in/ft for 3-inch pipe.

A backwater valve is required on the building sewer where the building drain is below the level of the public sewer or where the sewer may surcharge.

Sewer joints must be watertight and root-resistant; clay tile, cast iron, PVC, and ductile iron are common materials, and the pipe must be bedded per the manufacturer's instructions.

A cross-connection is any actual or potential connection between the potable water system and a source of contamination; it must be eliminated or protected by an approved backflow preventer.

An air gap is the only absolute protection against backflow; it must be at least twice the diameter of the supply pipe and never less than 1 inch above the flood-level rim.

A reduced pressure zone (RPZ) assembly is required for high-hazard connections (e.g., boiler feed, chemical injection, irrigation with fertilizer); it must be tested annually by a certified tester.

A double check valve assembly is used for low-hazard connections and must be tested annually; a pressure vacuum breaker is used for lawn irrigation and must be installed 12 inches above the highest downstream outlet.

A hose bibb vacuum breaker is required on all sill cocks and hose connections; it must be listed and must not be removed.

Backflow preventers must be installed in an accessible location, protected from freezing, and not installed below grade unless in a vault with drainage.

The potable water system must be protected from contamination during construction by caps and plugs; a final disinfection with chlorine (50 ppm for 24 hours or 200 ppm for 3 hours) is required for new mains.

A plumbing permit is required to install or replace a backflow preventer, and the assembly must be inspected and tested after installation.

Personal protective equipment: safety glasses with side shields, gloves, hard hat, and steel-toe boots are required on construction sites; hearing protection is required when noise exceeds 85 dBA.

Confined spaces (excavations deeper than 4 ft, tanks, vaults) require atmospheric testing for oxygen, flammable gas, and hydrogen sulfide before entry and continuous monitoring during entry.

Trench protection: any excavation 5 ft or deeper requires a protective system (sloping, shoring, or trench box); spoil piles must be kept at least 2 ft from the edge.

Before digging, call 811 to locate underground utilities and wait the required time (typically 48 hours in Louisiana); hand-dig within 24 inches of marked utilities.

Soldering copper requires a fire watch and a fire extinguisher; remove or protect combustible materials within 18 inches of the work area.

A pipe wrench is sized by the pipe diameter it fits; use a backing wrench on the opposite side of a fitting to prevent damage to the pipe or valve.

A hydrostatic test is the standard for DWV systems: fill the system with water to at least 10 ft of head above the highest fitting and hold for 15 minutes before inspection.

Lockout/tagout procedures must be followed before servicing gas or electrical equipment; verify the energy source is isolated and tagged before work begins.

Copper tube types: K (thickest, underground), L (standard, most common), M (thin wall, aboveground only); type M is not permitted underground.

PEX tubing must be protected from sunlight and must not be installed within 12 inches of a heat source; it must be supported per the manufacturer's instructions and tested with water.

Water piping must be tested at 50 psi or working pressure, whichever is greater, for at least 60 minutes; the test must be witnessed by the code official.

A water service must have a main shutoff valve, a meter, and a pressure-reducing valve if the supply pressure exceeds 80 psi.

Hot water piping must be insulated where required by the energy code; cold water piping must be insulated where it may sweat or freeze.

A water hammer arrestor must be installed at the end of a long run and at quick-closing valves; it must be accessible for maintenance.

Backflow prevention is required at the water service connection if a boiler, irrigation system, or chemical injection is connected.

Pipe hangers and supports must be listed and sized for the pipe; plastic pipe must be supported with hangers that do not damage the pipe.

A water closet must be installed with a 4-inch drain and a water supply with a stop valve; the flange must be secured to the floor and the closet must be level.

A lavatory must have a 1-1/4 inch trap and drain; a bathtub must have a 1-1/2 inch drain; a water closet must have a 3-inch or 4-inch closet bend.

A floor drain must have a trap with a minimum 2-inch seal and a strainer; a trap primer is required where the trap may evaporate.

A dishwasher must have an air gap or high-loop drain connection to prevent backflow; the discharge must connect to the sink drain or a separate trap.

A clothes washer requires a 2-inch standpipe with a trap and a 2-inch vent; the standpipe must be at least 18 inches and not more than 42 inches above the floor.

A water heater must be installed with a temperature and pressure relief valve, a discharge pipe terminating within 6 inches of the floor, and a drain pan where leakage could cause damage.

Fixture clearances: a water closet requires at least 15 inches from centerline to side wall and 21 inches in front of the bowl; a lavatory requires 15 inches centerline to side wall.

A fixture must be installed with a water supply and a drain; the fixture must be accessible for cleaning and repair, and the trap must be accessible.

A temperature and pressure relief valve is required on every water heater; its discharge pipe must be full size, terminate within 6 inches of the floor, and not be trapped or reduced.

A water heater must have a shutoff valve on the cold water inlet and a union or flange for removal; the T&P valve must be piped to a safe location.

Gas piping must be sized per the longest length method or branch length method using the tables; pressure drop is limited to 0.5 in w.c. for natural gas at low pressure.

Gas pipe must be supported at 6 ft intervals and protected from physical damage; a sediment trap is required at the appliance connection.

Gas piping must be tested with air or inert gas at 10 psi for at least 30 minutes for systems up to 125 psi working pressure; the test must be witnessed by the code official.

A gas shutoff valve must be installed within 6 ft of the appliance and in the same room; a union must be installed downstream of the shutoff valve.

Flue and vent connectors must have a minimum 6-inch rise before any offset, and a draft hood must be installed per the appliance listing.

A water heater in a garage must be elevated so the ignition source is at least 18 inches above the floor unless listed as flammable-vapor ignition resistant.

The building sewer must be sized by the total DFU; minimum size is 4 inches for a building sewer serving a building with water closets, and 3 inches for a building with no water closets.

Sewer pipe must be laid on a uniform grade with a minimum slope of 1/4 in/ft for 4-inch pipe and 1/8 in/ft for 6-inch pipe; the invert must be at least 2 ft below the building drain.

A sewer cleanout is required at the property line, at the building sewer, and at intervals not exceeding 100 ft; cleanouts must be accessible and have a gas-tight cover.

Storm drainage must be separate from sanitary drainage; roof drains and area drains must discharge to a storm sewer or approved disposal system, not the sanitary sewer.

Roof drain sizing depends on the roof area, rainfall intensity (inches per hour), and the drain size; the 100-year, 1-hour rainfall intensity for the local area is used.

Storm drain pipe must be sized for the design flow and slope; the minimum size is 3 inches and the minimum slope is 1/4 in/ft for 3-inch pipe.

A backwater valve is required on the building sewer where the building drain is below the level of the public sewer or where the sewer may surcharge.

Sewer joints must be watertight and root-resistant; clay tile, cast iron, PVC, and ductile iron are common materials, and the pipe must be bedded per the manufacturer's instructions.

A cross-connection is any actual or potential connection between the potable water system and a source of contamination; it must be eliminated or protected by an approved backflow preventer.

An air gap is the only absolute protection against backflow; it must be at least twice the diameter of the supply pipe and never less than 1 inch above the flood-level rim.

A reduced pressure zone (RPZ) assembly is required for high-hazard connections (e.g., boiler feed, chemical injection, irrigation with fertilizer); it must be tested annually by a certified tester.

A double check valve assembly is used for low-hazard connections and must be tested annually; a pressure vacuum breaker is used for lawn irrigation and must be installed 12 inches above the highest downstream outlet.

A hose bibb vacuum breaker is required on all sill cocks and hose connections; it must be listed and must not be removed.

Backflow preventers must be installed in an accessible location, protected from freezing, and not installed below grade unless in a vault with drainage.

The potable water system must be protected from contamination during construction by caps and plugs; a final disinfection with chlorine (50 ppm for 24 hours or 200 ppm for 3 hours) is required for new mains.

A plumbing permit is required to install or replace a backflow preventer, and the assembly must be inspected and tested after installation.

Personal protective equipment: safety glasses with side shields, gloves, hard hat, and steel-toe boots are required on construction sites; hearing protection is required when noise exceeds 85 dBA.

Confined spaces (excavations deeper than 4 ft, tanks, vaults) require atmospheric testing for oxygen, flammable gas, and hydrogen sulfide before entry and continuous monitoring during entry.

Trench protection: any excavation 5 ft or deeper requires a protective system (sloping, shoring, or trench box); spoil piles must be kept at least 2 ft from the edge.

Before digging, call 811 to locate underground utilities and wait the required time (typically 48 hours in Louisiana); hand-dig within 24 inches of marked utilities.

Soldering copper requires a fire watch and a fire extinguisher; remove or protect combustible materials within 18 inches of the work area.

A pipe wrench is sized by the pipe diameter it fits; use a backing wrench on the opposite side of a fitting to prevent damage to the pipe or valve.

A hydrostatic test is the standard for DWV systems: fill the system with water to at least 10 ft of head above the highest fitting and hold for 15 minutes before inspection.

Lockout/tagout procedures must be followed before servicing gas or electrical equipment; verify the energy source is isolated and tagged before work begins.