5.1 Water Service and Distribution Materials, and Sewer Separation
Key Takeaways
- IPC 603.1 requires the water service pipe to be not less than 3/4 inch in diameter, a floor repeated in IPC Appendix E104.1.
- IPC 603.2 requires 5 feet of undisturbed or compacted earth between a water service and a building sewer in the same trench unless the sewer uses Table 702.2 materials.
- IPC 603.2 allows a crossing without the 5-foot separation where the water service is sleeved 5 feet horizontally each side, or where the bottom of the water service within 5 feet of the sewer is at least 12 inches above the top of the sewer.
- IPC 605.2.1 limits pipe, fittings and fixtures conveying drinking water to a weighted average lead content of not more than 0.25 percent of the wetted surfaces.
- IPC 602.2 permits only potable water to be supplied to fixtures used for drinking, bathing, culinary purposes, or processing of food, medical or pharmaceutical products.
Scope and the potable-water rule
IPC 601.1 governs the potable water supply from the source to the fixture. IPC 602.1 requires structures with plumbing fixtures used for human occupancy or habitation to be supplied with potable water in the amounts and pressures the chapter specifies, and IPC 602.2 narrows it:
Only potable water shall be supplied to plumbing fixtures that provide water for drinking, bathing or culinary purposes, or for the processing of food, medical or pharmaceutical products. Unless otherwise provided in this code, potable water shall be supplied to all plumbing fixtures.
Three other Section 601 rules matter on the exam:
- 601.2 Solar energy utilization: solar systems for heating potable water must comply with Chapter 6 and the relevant standards.
- 601.3 Existing piping used for grounding: where a metallic water service is replaced with nonmetallic pipe, the electrical grounding must be addressed — the plumber cannot simply sever the ground path.
- 601.4 Tests: the potable water system is tested under IPC 312.5 (working pressure with water, or 50 psi with air on non-plastic piping, 15 minutes).
Individual water supply — IPC 602.3
Where a public potable supply is not available, an individual source is used. Acceptable types: drilled well, driven well, dug well, bored well, spring, stream or cistern. Surface bodies of water and land cisterns shall not be sources unless properly treated by approved means. Where state and local law does not address a requirement, NGWA-01 fills the gap.
| Section | Requirement |
|---|---|
| 602.3.2 | Combined capacity of source and storage must supply fixtures at the chapter's rates and pressures |
| 602.3.3 | Water must be approved as potable by the authority having jurisdiction before connection |
| 602.3.4 | The system must be purged and disinfected per Section 610 after construction |
| 602.3.5 | Pumps rated for potable water; drinking-water pumps conform to NSF 61; sealed to the casing or covered with a watertight seal; designed to maintain prime; ready access to all parts |
| 602.3.5.1 | Pump rooms drained and freeze-protected; basement pumps mounted on a block or shelf not less than 18 inches above the floor; well pits are prohibited |
IPC 608.18 completes the picture with minimum separation distances from contamination:
| Source of contamination | Minimum distance |
|---|---|
| Barnyard, pasture | 100 feet |
| Seepage pits, subsurface disposal fields, subsurface pits | 50 feet |
| Farm silo, septic tank | 25 feet |
| Sewer | 10 feet |
| Pumphouse cast-iron floor drain draining to ground surface | 2 feet |
Well sites must be positively drained and at higher elevations than potential contamination sources (608.18.2).
Water service size and trench separation
IPC 603.1: the water service pipe is sized for the quantities and pressures the code requires and shall be not less than 3/4 inch in diameter. Appendix E104.1 repeats the 3/4-inch floor.
IPC 603.2 Separation of water service and building sewer has one rule and three ways out:
Where water service piping is located in the same trench with the building sewer, such sewer shall be constructed of materials listed in Table 702.2 (underground building sanitary drainage pipe). Where the sewer is not of those materials, the water service and the building sewer shall be horizontally separated by not less than 5 feet of undisturbed or compacted earth.
Exceptions to the 5-foot separation:
- Crossings, provided the water service is sleeved to a point not less than 5 feet horizontally from the sewer centerline on both sides of the crossing. The sleeve is pipe material from Table 605.3, 702.2 or 702.3.
- Where the bottom of the water service pipe, within 5 feet of the sewer, is not less than 12 inches above the highest point of the top of the building sewer.
- Where the sewer itself is built of Table 702.2 materials, sharing the trench is permitted outright.
IPC 603.2.1: potable water service pipes shall not be located in, under or above cesspools, septic tanks, septic tank drainage fields or seepage pits.
IPC 605.1 Soil and ground water: where the water service is installed in corrosive soil or where soil or ground water conditions are suspect, the material must be approved for the condition or an analysis is required.
Lead content
| Section | Limit |
|---|---|
| 605.2 | Pipe and fittings used in the water supply system shall have a maximum of 8 percent lead |
| 605.2.1 | Pipe, pipe fittings, joints, valves, faucets and fixture fittings used to supply water for drinking or cooking shall have a weighted average lead content of the wetted surfaces of not more than 0.25 percent, and shall conform to NSF 372 |
The 0.25 percent rule is what "lead free" means in modern practice. Solder and flux in potable water piping must contain not more than 0.2 percent lead (605.12.3, 605.13.6).
Approved materials
Table 605.3 Water service pipe and Table 605.4 Water distribution pipe list what may be used. The materials you meet routinely:
| Material | Water service (605.3) | Water distribution (605.4) |
|---|---|---|
| Copper or copper-alloy pipe and tubing (Type K, WK, L, WL, M or WM) | yes | yes |
| CPVC and CPVC/AL/CPVC | yes | yes |
| PEX, PEX-AL-PEX and PEX-AL-HDPE | yes | yes |
| PE-RT | yes | yes |
| Polypropylene (PP) | yes | yes |
| PE-AL-PE | yes | yes |
| Galvanized steel | yes | yes |
| Ductile iron | yes | yes |
| Stainless steel (Type 304/304L, 316/316L) | yes | yes |
| PVC | yes | no |
| PE pipe and PE tubing | yes | no |
| ABS | yes | no |
The single most useful line in those two tables: PVC, PE and ABS are water service materials only. PVC is not listed for water distribution inside the building — CPVC is. Confusing the two is a classic exam trap and a classic field failure, because ordinary PVC is not rated for the temperature of hot water distribution.
Two pressure ratings travel with those tables. IPC 605.3: water service pipe shall conform to NSF 61, and pipe or tubing installed underground and outside the structure shall have a working pressure rating of not less than 160 psi at 73.4 degrees F. IPC 605.4: water distribution pipe shall conform to NSF 61, and hot water distribution pipe and tubing shall have a pressure rating of not less than 100 psi at 180 degrees F.
IPC 605.3.1: where a dual check-valve-type backflow preventer is installed on the water service, thermal expansion control becomes necessary under 607.3, because the service is now closed.
Table 605.5 Fittings lists fittings by material. IPC 605.5.1 Mechanically formed tee fittings permits collared branch outlets formed in copper tube, but only when made with the listed tool and brazed — not soldered.
Valves and prohibited below-grade outlets
Table 605.7 lists the standards for valves — ball, butterfly, check, gate, globe, plug. IPC 605.6 requires flexible water connectors exposed to continuous pressure to conform to ASME A112.18.6/CSA B125.6.
IPC 608.8 is short and often tested:
Potable water outlets and combination stop-and-waste valves shall not be installed underground or below grade. A freezeproof yard hydrant that drains the riser into the ground shall be considered as having a stop-and-waste valve below grade.
Exception: such freezeproof yard hydrants are permitted provided the potable water supply to them is protected by a reduced pressure principle assembly (608.14.2) or a pressure vacuum breaker assembly (608.14.5), and the hydrants and the piping from the backflow preventer to the hydrant are identified per 608.9.
The logic: when the riser drains into the soil, the buried opening becomes a potential backsiphonage inlet from contaminated ground water. Hence backflow protection plus identification.
Existing piping and rehabilitation
IPC 601.5 Rehabilitation of piping systems: where pressure piping systems are rehabilitated using an epoxy lining system, that lining system shall comply with ASTM F2831. IPC 608.11 Reuse of piping prohibits reusing piping that has conveyed nonpotable water or other contaminating substances for potable water service or distribution.
A water service pipe shares a trench with a building sewer made of a material not listed in Table 702.2. What separation does IPC 603.2 require?
Which material is listed for water service piping but NOT for water distribution piping?
What is the maximum weighted average lead content of the wetted surfaces of pipe and fittings used to supply drinking water?
A freezeproof yard hydrant that drains its riser into the ground is proposed. What does IPC 608.8 require?