Whole-House Repiping in Palo Alto, CA

A Homeowner’s Guide to Whole-House Repiping in Palo Alto

How old Palo Alto’s houses are

Palo Alto’s 2023–2031 Housing Element (certified August 2024) says the city grew fastest in the decade after World War II, and it puts the median build year of a Palo Alto home at 1955. Its Table 2-38, from 2016–2020 Census estimates:

Year built	Share of homes
1939 or earlier	13.1%
1940 to 1949	7.8%
1950 to 1959	26.4%
1960 to 1969	13.7%
1970 to 1979	12.3%
1980 or later	26.7%

The City notes that more than half of the units were built over 50 years ago, while many have been upgraded since. Original supply pipe from those decades, especially galvanized steel, rusts inside, narrows and starts to leak at threaded joints. Use our repiping cost calculator for a first estimate, and see whole-house repiping.

Eichlers: new routes instead of the slab

Eichler Homes built some 2,700 houses in Palo Alto, in tracts from University Gardens (1949–1950) to Greenmeadow No. 3 (1961–1962) and three small ones in the 1970s. Section 5.5 of the City’s Eichler guidelines explains why their plumbing is different: it was placed in the concrete slab, along with the original radiant heating, and may be difficult to repair without highly invasive work.

For a repipe the guidelines point to two routes:

• Low-profile floor systems, which they call more efficient than overhead methods when in-slab plumbing must be replaced;
• Over the roof, placed where it won’t be highly visible from the street.

The same section notes that Eichlers lack attic spaces, so routes are planned room by room before any wall is opened. Single leaks can often be fixed without a full repipe; see slab leak repair and leak detection.

The permit and the inspection

A licensed contractor can get an instant building permit through Accela Citizen Access to re-pipe the water system of a detached single-family home or duplex, interior only, with no sewer lines. Other standalone water work can use the Over-the-Counter Residential MEP Permit Pilot.

The Building Division’s repipe checklist (revised 2011) shows what it looks for:

• grounding and bonding brought up to the electrical code whenever metal water piping is modified, with a label at the electric panel if the service becomes non-metallic;
• approved transitions where copper meets galvanized;
• Type L copper with brazed joints in or under a slab;
• insulation on the first 5 feet of hot and cold pipe at the water heater;
• a pressure regulator where static pressure exceeds 80 psi, typically west of El Camino Real.

Damaged shear walls, fire walls or stucco take a separate permit.

From the meter to the house

Under CPAU Rule 21, the City maintains the service up to and including the meter; the owner maintains everything downstream, meter box included. A repipe usually starts at the house valve, but an old yard line can be replaced at the same time. A residential remodel or addition valued over $200,000 requires replacing a water service that isn’t copper or polyethylene, from the main through the meter box. See water line replacement.

Water quality and the water heater

CPAU’s 2025 water quality report shows hardness averaging 62 ppm, soft for the region, and no lead service lines in the City’s system. If the water heater is due, replacing it during the repipe saves reopening the same connections; CPAU’s heat pump water heater rebates must be reserved before the work starts. Compare other cities in our South Bay water hardness table.

Sources

City of Palo Alto: 2023–2031 Housing Element (Table 2-38) · Eichler Neighborhood Design Guidelines (2018) · Apply for a Building Permit · Over-the-Counter Residential MEP Permit Pilot Program · Repipe inspection checklist (rev. 2011). City of Palo Alto Utilities: Rule 21, Special Water Utility Regulations (effective June 1, 2026) · 2025 water quality report · Rebate Hub. Checked October 2026.