Commercial Plumber in Gilroy, CA

A Property Manager’s Guide to Plumbing in Gilroy

Water and sewer are run by the City

The City of Gilroy owns and operates its own water and wastewater utilities through a Utilities Department, created in 2024 out of Public Works. It maintains the City’s wells, pumps, reservoirs and distribution pipes, and a sewer system of about 167 miles of gravity pipe with more than 14,200 lateral connections. Wastewater flows to the treatment plant of the South County Regional Wastewater Authority (SCRWA), a joint powers authority that treats wastewater for Gilroy and Morgan Hill.

Save the City’s numbers with your building’s emergency contacts: the Utilities Department at (408) 846-0219 during business hours, and 408-846-0350, which the City’s water page lists for extreme water leaks between 3:30 p.m. and 7 a.m.

Sewer laterals: curb to building is the owner’s

The City’s guidance is that property owners are responsible for the water and sewer lines from the curb to the building. Roots won’t usually break a sound pipe but will get into cracks and failed joints, and the City’s Urban Forestry staff won’t remove a street tree solely because of roots in a line. That leaves the owner to keep the lateral in good condition and cleared.

The City’s design standards for new laterals call for 4-inch minimum pipe at a 2% minimum slope and an accessible two-way cleanout at the back of the sidewalk. On older properties without one, a cleanout and a camera inspection of the lateral are worth planning. See commercial sewer repair.

Restaurants and other kitchens: the SCRWA pretreatment program

Commercial grease rules in Gilroy are set through SCRWA. The Industrial Wastewater Pretreatment Program, a sub-program of SCRWA run by the City’s Fire Prevention Division, serves Gilroy and Morgan Hill. The key points:

• Permits: any wastewater other than restrooms and hand sinks counts as industrial wastewater. Restaurants and laundromats generally fall in the significant user class. The permit application is filed for new permits, changes, renewals and changes of ownership or operator.
• Grease interceptors: SCRWA’s Sewer Use Ordinance requires one at restaurants, bakeries, hotels, markets, hospitals and similar businesses, serving that business only, accessible at all times and installed to the Plumbing Code with SCRWA approval. Toilets and urinals can’t drain through it, and remodeled buildings are covered too.
• Plan review: installing, modifying or removing a wastewater treatment system, such as an interceptor, needs the program’s plan review and inspection.
• Records: keep 3 years of grease removal reports or contractor receipts on site, plus a maintenance log when your own staff service an in-kitchen grease trap. The City’s log form says to service the trap when solids pass 25% of capacity or any grease shows at the inspection port.
• Inspections: inspectors may come by appointment or unannounced, and significant users are generally inspected every year.

Car washes and similar sites with a sand and oil interceptor keep an inspection log for at least 3 years and inspect the interceptor at least twice a year. Scheduled hydro jetting keeps the kitchen lines leading to the interceptor open.

Permits through GO Permit

The Building Division requires permits for extensions to plumbing systems, water heater replacements and additions, and sewer and water services. Applications go through GO Permit, the City’s online system for residential and commercial projects, which also handles engineering encroachment and fire permits, plan review tracking and inspection scheduling. In October 2026 the City’s inspections page said appointments were booked about 72 hours out, and a same-day cancellation or missed inspection can bring a reinspection fee. The Building Division counter at City Hall is open Monday through Thursday, 8:30 a.m. to 4:30 p.m., at 408-846-0451.

Backflow testing

The Utilities Department runs the State-required backflow program to protect Gilroy’s drinking water. Backflow assemblies must be tested every year by a licensed tester. For a new 1- to 2-inch service that needs a device, the City’s technical specifications have Water Operations lock the meter until the device is installed; once the water is on, the contractor has 7 days to have a City-approved tester test it and send the report to Water Operations. We install and repair the assemblies these rules require; see backflow preventers.

Water heaters: hard well water and SVCE rebates

Gilroy’s drinking water is pumped from nine City wells in the Llagas Subbasin, which Valley Water manages and recharges; Valley Water doesn’t deliver treated water to Gilroy. The 2025 water quality report shows hardness averaging 237 ppm, ranging from 174 to 271 ppm (sampled February 2024). Water that hard builds scale in tanks, tankless heat exchangers and fixtures, so flushing and descaling matter.

When it’s time to replace, Gilroy is in Silicon Valley Clean Energy’s service area. SVCE offers business rebates for heat pump water heaters that replace gas or electric resistance units in existing buildings, with a separate commercial tier for tanks of 81 gallons or more. A reservation number is required before installation, and the claim needs proof of permitting. See commercial water heaters.

Also worth knowing

Under the State’s non-functional turf law (AB 1572), commercial, industrial and institutional properties must stop watering decorative grass with drinking water from January 1, 2028, and HOA common areas from January 1, 2029; the City’s page has the details and exemptions.

Sources

City of Gilroy: Utilities Department · Water · Wastewater collection · Wastewater treatment · Tree roots in sewer and water lines (FAQ) · General Guidelines (2014) · Technical Specifications (2014) · Industrial Wastewater Pretreatment Program · SCRWA Sewer Use Ordinance 2024-01 · Pretreatment permit application · Grease trap maintenance log · Water Backflow Testing Program · Building Division · GO Permit · Building inspections · 2025 water quality report · Non-functional turf ban. Silicon Valley Clean Energy: Service area · Business rebate equipment specifications. Checked October 2026.