Water Heater Repair and Replacement in Sunnyvale, CA

A Homeowner’s Guide to Water Heater Repair and Replacement in Sunnyvale

The permit and the final inspection

Sunnyvale treats every water heater replacement as permit work, and its brochure says the permit comes before the installation. For most homes the path is short:

• Apply: online through the City’s Permit Center, or at the One-Stop Permit Center at City Hall, 456 W. Olive Ave. (408-730-7444), weekdays 8 a.m. to noon and 1 to 5 p.m.
• Inspect: one final inspection after the work is done. A new electric water heater also needs an electrical inspection before the final.

We pull the permit and meet the inspector as part of a replacement. See water heater repair and replacement.

What the City’s brochure asks for

The Residential Water Heater Replacement brochure (rev. 12/2025) applies to permits submitted from January 1, 2026 and reads like the inspector’s checklist:

• Seismic straps: one in the top third and one in the bottom third, the lower strap at least 4 inches above the controls. Two straps up to 52 gallons, three at 75 gallons, four at 100 gallons. A platform under the heater must be fastened to the structure or slab.
• Relief valve drain: galvanized steel, hard copper or CPVC, full valve size (usually 3/4 inch) to the outside, untrapped, unthreaded at the end, pointing down 6 to 24 inches above the ground. Never into a crawl space or a pan.
• Venting (gas units): double-wall metal pipe through ceilings, floors and walls, kept the maker’s distance from framing (typically 1 inch), ending at least 1 foot above the roof under a listed cap and 3 feet above any opening within 3 feet.
• Garage: pilot and controls 18 inches above the floor unless the unit is flammable-vapor ignition resistant, and a barrier where a car could hit it.
• Attics and closets: a 1-1/2-inch-deep pan with a 3/4-inch drain where a leak could damage framing; two 100-square-inch combustion air openings for a gas heater in a closet; a gasketed self-closing door if the closet opens off a bedroom or bathroom.
• Gas line: a sediment trap after the appliance shutoff, close to the inlet.

The brochure doesn’t mention expansion tanks, but the California Plumbing Code (608.3) requires one wherever a check valve, backflow preventer or other closed device keeps pressure from easing back to the main. We check for one on every replacement.

Tankless conversions

Gas tankless heaters must be listed and installed to the maker’s instructions, with Category II stainless venting. Because they burn more gas at once, a larger supply line may be needed, and PG&E requires 36 inches of horizontal clearance between the gas meter and a tankless unit on the same wall. See tankless water heaters and gas line services.

Water quality by neighborhood

Sunnyvale’s 2025 Water Quality Report lists three sources:

Source	Where it goes	Average hardness (2025)
SFPUC (mostly Hetch Hetchy)	Northern Sunnyvale	60 ppm (range 8.1–112)
Valley Water treated surface water	Southern Sunnyvale	97 ppm (96–98)
Six City wells	Added at summer peaks and in emergencies	290 ppm (270–310)

The report itself lists longer water heater life among the benefits of softening. On Valley Water and well water, flush tanks yearly and descale tankless heat exchangers on the maker’s schedule.

Gas, heat pumps and the 2027 rule

Under the 2025 Energy Code, the City’s brochure allows a replacement to be gas, propane or a heat pump water heater, and an electric resistance unit can be replaced with another electric one. Two changes are coming:

• Air District Rule 9-6: home gas water heaters of 75,000 BTU/hr or less manufactured after January 1, 2027 must be zero-NOx. On November 4, 2026 the Board votes on moving that date to January 1, 2028 and adding exemptions. The rule applies at purchase, not to working heaters. See the zero-NOx rules.
• Sunnyvale reach code: approved in August 2025 for existing single-family alterations, with enforcement from the end of 2026. As introduced, it asks for space and a condensate drain for a future heat pump water heater when wall framing within 3 feet of a gas water heater is removed or replaced, and a 240-volt-ready circuit or pathway when nearby circuits are altered under an electrical permit.

SVCE rebates for heat pump water heaters

Silicon Valley Clean Energy’s Home Rebates pay toward a heat pump water heater replacing gas or electric resistance in homes of up to four units. The April 2026 specifications require 40 gallons or more, NEEA Tier 3 or higher, a thermostatic mixing valve and proof of permit; tankless models don’t qualify. Reserve before installing; reservations hold up to 120 days, and SVCE has a process for emergency replacements. Its separate Emergency Water Heater Replacement program uses SVCE’s partner contractors. See SVCE heat pump rebates and heat pump water heaters.

Sources

City of Sunnyvale: Permits · Single-Family and Duplex Residential · Residential Water Heater Replacement (rev. 12/2025) · 2025 Water Quality Report · Electrify Your Home · Report to Council 25-0762 (Aug. 12, 2025). State of California: 2025 California Plumbing Code. Silicon Valley Clean Energy: Home Rebates · Appliance Specifications, April 2026 · Service area · Emergency Water Heater Replacement. Bay Area Air District: Rules 9-4 and 9-6 Building Appliances · Building Appliances Rule Implementation. Checked October 2026.