8.1 Water Service, Pipe Materials, Joints, Valves, Pressure Control & Disinfection

Definitions

• Water service pipe: the pipe from the water main or other potable source (or from the meter when the meter is at the public right of way) to the building's water distribution system.
• Water distribution pipe: pipe within the structure or on the premises that carries water from the water service, or from the meter when it is at the structure, to the points of use.
• Potable water: water free from impurities in amounts that could cause disease or harmful physiological effects, and meeting the drinking water standards of the public health authority.

The water service (IPC 603)

• 603.1: the water service must be sized to supply the required quantity and pressure, and must be at least 3/4 inch in diameter.
• 603.2: separation from the building sewer (see Section 5.2): a shared trench is allowed only if the sewer is made of Table 702.2 materials. Otherwise, keep 5 feet of horizontal separation, unless the water service is sleeved for 5 feet on each side of a crossing, or its bottom is at least 12 inches above the top of the sewer.
• 603.2.1: a water service must not be in, under or above cesspools, septic tanks, drain fields or seepage pits. Where soil or groundwater might contaminate the pipe, an analysis is required (605.1).
• Virginia 603.3 tracer wire: nonmetallic water service piping that connects to a public system must be locatable. Use insulated copper tracer wire of at least 18 AWG suitable for direct burial, in the same trench and within 12 inches of the pipe, from within 5 feet of the building wall to the connection with the public supply. At least one end must terminate above grade in an accessible location that resists damage, such as a meter vault or the building wall.
• 305.4: exterior water supply piping must be at least 6 inches below the frost line and 12 inches below grade.
• 605.1: a water service or distribution pipe must not be installed in soil or groundwater contaminated with solvents, fuels or organic compounds that could cause permeation, corrosion or failure. Where such conditions are suspected, a chemical analysis is required.

Materials (IPC 605.3 and 605.4)

Water service pipe (605.3) must conform to NSF 61 and one of the standards in Table 605.3. When installed underground outside the structure, it must have a working pressure rating of at least 160 psi at 73.4°F, or higher if the water pressure exceeds 160 psi. Material that is not third-party certified for water distribution must end at or before the full-open valve at the building entrance. Ductile iron water service must be cement-mortar lined (AWWA C104).

Water distribution pipe (605.4) must conform to NSF 61 and one of the standards in Table 605.4. Hot water distribution pipe must be rated at least 100 psi at 180°F.

Two common mistakes: copper Type M is listed for water service in Table 605.3, and PVC is not listed in Table 605.4 for water distribution. PVC therefore stops outside the building, or at the full-open valve at the entrance if it lacks third-party certification for distribution.

Lead (IPC 605.2 and solder sections)

• 605.2: pipe and fittings, including valves and faucets, used in the water supply system may have no more than 8% lead.
• Virginia 605.2.1: pipe, fittings, joints, valves, faucets and fixture fittings that supply water for drinking or cooking must comply with NSF 372, the low-lead standard (a weighted average of 0.25% lead on wetted surfaces).
• 605.12.3 and 605.13.6: solder joints follow ASTM B828, with tube ends reamed, ASTM B813 flux, and ASTM B32 solder. Water supply joints use lead-free solder and flux, meaning 0.2% lead or less. Solder and flux for drinking water must conform to NSF 61.

Joints (IPC 605.9 to 605.24)

• 605.9 prohibited joints: cement or concrete joints; joints made with fittings not approved for the installation; solvent-cement joints between different types of plastic; and saddle-type fittings.
• 605.14.2 CPVC: where the manufacturer requires primer, use primer and orange ASTM F493 cement. A one-step yellow ASTM F493 cement may be used without primer where the manufacturer allows it. Virginia 605.15.2 allows the CPVC/AL/CPVC primer exception where the solvent cement is yellow or green.
• 605.21.3 PVC: purple primer (ASTM F656) and ASTM D2564 cement.
• 605.14.3 and 605.21.4 threaded plastic: threading requires at least Schedule 80 pipe, and the pressure rating is reduced by 50%.
• 605.23: joints between different materials use compression or mechanical-sealing joints with elastomeric seals meeting ASTM F477. 605.23.1: copper to galvanized steel uses a copper-alloy or dielectric fitting, or an ASSE 1079 dielectric union.
• 605.13.7: push-fit fittings meet ASSE 1061.

Valves (IPC 606)

606.1 full-open valves are required:

1. on the water service near the curb;
2. on the distribution supply at the entrance into the structure;
3. for each tenant in multiple-tenant buildings with a common supply (other than one- and two-family dwellings);
4. on the discharge side of every water meter;
5. at the base of every water riser, except in one- and two-family homes and in multifamily buildings two stories or less;
6. at the top of every down-feed pipe, except in one- and two-family homes;
7. at the entrance to every dwelling unit, except where it supplies a single fixture with individual stops;
8. on the supply to a gravity or pressurized water tank;
9. on the supply to every water heater.

606.2 shutoff valves are required: on the supply to each plumbing fixture, except bathtubs and showers in one- and two-family dwellings and sleeping units that have unit shutoffs; on the supply to each sillcock; and on the supply to each appliance or piece of mechanical equipment. 606.3 requires access to all full-open and shutoff valves. 606.4 requires service and hose bibb valves, and valves not next to the fixture they serve, to be identified.

503.1: the cold water branch to each water heater needs its own valve near the heater, on the same floor, serving only the heater.

Pressure (IPC 604.6 to 604.9 and 606.5)

• 604.6: where main pressure fluctuates, design for the minimum pressure available.
• 604.7: if pressure is too low to meet Table 604.3, install a booster system under 606.5.
• 604.8 pressure-reducing valve: where static pressure in the building exceeds 80 psi, install an approved PRV meeting ASSE 1003 or CSA B356, with a strainer, to reduce distribution pressure to 80 psi static or less. Exception: service lines to sillcocks and outside hydrants, and main risers where pressure is already reduced to 80 psi or less at each fixture.
• 604.8.1: the PRV must be designed to remain open so flow continues if the valve fails.
• 604.8.2: PRVs, regulators and strainers must allow repair or removal of parts without breaking a pipeline or removing the valve and strainer.
• 607.3: if a storage water heater is supplied through the PRV (or a check valve or backflow preventer), thermal expansion control is required (see Section 8.3).
• 604.9 water hammer: control flow velocity to reduce water hammer. A water hammer arrestor shall be installed where quick-closing valves are used, per the manufacturer, and arrestors must conform to ASSE 1010. An arrestor is a sealed device with a cushion of gas behind a piston or bellows. A capped air-chamber stub is not an ASSE 1010 arrestor; it waterlogs and stops working.
• 606.5 boosters: where main pressure is insufficient, use an elevated tank, a hydropneumatic booster system or a booster pump. A low-pressure cutoff must stop a booster pump when suction pressure falls to 10 psi or less (606.5.5). Gravity tank inlets need an air gap of at least 4 inches above the overflow (606.5.6). Pressure tanks need a vacuum relief valve of at least 1/2 inch, except captive-air bladder tanks (606.5.9), and hydropneumatic tanks need a pressure relief valve set no higher than the tank rating (606.5.10).

Testing and disinfection

• 312.5: test at not less than the system working pressure with water, or, for non-plastic piping, with air at 50 psi or more. Hold for 15 minutes, using water from a potable source.
• 610.1 disinfection: new potable systems must be purged and disinfected before use, by the method of the health authority or water purveyor, or AWWA C651 or C652, or the code method:
  1. Flush with clean potable water until dirty water no longer appears at the outlets.
  2. Fill with a chlorine solution of at least 50 ppm and let it stand 24 hours, or at least 200 ppm and let it stand 3 hours.
  3. Flush with clean potable water until the chlorine is purged.
  4. Repeat if a bacteriological test shows contamination remains.