Water Service Pipe Sizing

Size domestic water service and building main per NJ UCC Plumbing Subcode 2021 (NSPC). Tables 10.14.2A and 10.14.2B. Separate hot and cold water pipe sizing with 3/4 rule.
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Sizing Method

NSPC Tables B.7.3: Direct lookup — pipe sized from code tables by WSFU at a given velocity. Includes pressure drop per 100ft.
Hazen-Williams: Friction loss calculation against available pressure budget. More precise for long runs and complex systems.

Occupancy Type — Table 10.14.2A Column

Bathroom Groups — 1.6 GPF Tank WC

1 Bathroom Group = 1 WC + up to 2 lavs + 1 tub or shower. Half-Bath = 1 WC + 1 lav. Other fixtures count separately.

Group	WSFU	Qty

Individual Fixtures — Table 10.14.2A

Fixture	WSFU	Branch	H/C	Qty

Water Pressure

Street Pressure (psi)

Pressure Budget

Elevation (ft)

0.433 psi/ft

Meter Loss (psi)

BFP Loss (psi)

PRV Loss (psi)

Other (psi)

Min Fixture Pressure

Pipe

Service Line (Main to Building)

Material

Developed Length (ft)

Cold Water Main (Building Distribution)

Material

Developed Length (ft)

Hot Water Main (After Water Heater)

Material

Developed Length (ft)

Hot water in copper: max 5 FPS (10.14.1). Cold: max 8 FPS. Dev length = actual + ~50% for fittings.

Booster Pump

Results

Per NJ UCC Plumbing Subcode 2021 (NSPC), Tables 10.14.2A and 10.14.2B. WSFU values and GPM conversion are from the code text. The 3/4 hot/cold split rule is per Note 4. Hot water piping uses the flush tank column per Note 2. Verify with current adopted code and local utility. Green Stories LLC is a building design and consulting firm.