Commercial Plumber in Los Altos, CA

A Property Manager’s Guide to Plumbing in Los Altos

Water: Cal Water’s Los Altos Suburban District

The City of Los Altos doesn’t run a water system. California Water Service (Cal Water) supplies the city through its Los Altos Suburban District, which also serves parts of Cupertino, Los Altos Hills, Mountain View and Sunnyvale. Cal Water lists (650) 917-0152 as both its main and after-hours number. The district office at 949 B Street doesn’t offer in-person service, so plan on phone or email. Check the water bill to confirm the provider for a given building.

Sewer: run by the City, treated in Palo Alto

The City’s Maintenance and Services division maintains the wastewater collection system. Wastewater goes to the Palo Alto Regional Water Quality Control Plant, which the City of Palo Alto owns and operates for Los Altos and its other partners. Save the City’s numbers with your building’s emergency contacts:

• Municipal Service Center: 650-947-2785 during business hours (707 Fremont Avenue).
• After hours, weekends and holidays: Los Altos Police dispatch, 650-947-2770. Standby crews respond 24 hours a day.

A City crew checks the main and clears it if needed. Where there is an accessible property-line cleanout, the crew also checks the lateral between the cleanout and the main and clears a blockage there as a courtesy. If the main is flowing and the blockage is in the lateral, the owner calls a plumber.

Sewer laterals: owner cleans, repairs are split

Under Municipal Code §10.04.290, the owner is responsible for cleaning and maintaining the street and house lateral all the way to the main, and the City pays no plumbing bills except when a street lateral needs reconstruction or repair. For reconstruction, the line splits at the first joint after the property line: the owner rebuilds from there to the building, the City from there to the main. If a plumber can’t clear a stoppage because of a defect, the City repairs it when the defect is beyond the first full section of pipe past the cleanout.

The City’s share is tied to its cleanout rule (§10.04.250): a cleanout where the building sewer joins the lateral, kept watertight, under a City-approved box set flush with the ground. The City recommends installing a property-line cleanout where there isn’t one. A few other code rules matter for multi-building sites: adjacent buildings on the same street can’t share a side sewer unless they have the same owner, and root killers containing more than 5% copper may not go into the sewer. For older properties, a cleanout plus periodic camera inspection is worth planning. See commercial sewer repair.

Restaurants: grease rules in the City code

Los Altos writes its grease rules into Municipal Code chapter 10.08:

• Grease removal device: required for each grease-generating activity, sized to the plumbing code, kept in good repair and in continuous operation.
• Pumping: as often as needed to stay within the code’s limits, and at least every six months.
• Records: a log of each removal (date, amount and where it went), kept for 3 years and shown to City inspectors on request.
• No grease down the drain: disposing of grease into any sewer, storm drain or onto land is prohibited.

New, remodeled or converted food service facilities also need a sink or area for washing floor mats and equipment that drains through a grease interceptor, and new food service buildings need a covered, bermed dumpster area. Scheduled hydro jetting keeps the kitchen lines leading to the interceptor open.

Permits and inspections

The Building Division (650-947-2752) takes plans, documents and the completed application, including its commercial permit application, by email only; hard copies aren’t accepted at City Hall. Submittals are processed within a few business days, then fees are paid and the project is routed for review. Approved permits and plans come back by email and must be printed and on site for inspection. The City’s eTRAKiT portal handles only certain simple residential permits. Commercial construction is allowed 7 a.m. to 7 p.m. on weekdays and 9 a.m. to 6 p.m. on Saturdays, not on Sundays or City holidays.

Sewer work has its own rules in the Municipal Code: a written City permit for any work on a lateral or building sewer, a water test in front of the City’s inspector, written notice at least 24 hours before inspection, and a separate excavation permit for digging in a public street. When commercial space is built, remodeled or converted, chapter 10.08 adds more: interior parking garage floor drains go to an interceptor and the sanitary sewer, boiler drains go to the sewer, condensate lines may not drain to the storm drain, and copper, brass and lead may not be used in sewer lines that touch sewage (sink traps excepted).

Backflow testing

Cal Water runs the cross-connection control program. Property owners are responsible for air gaps and backflow assemblies on their side of the meter where required; assemblies must be tested every year by certified backflow testers, and air gaps inspected yearly. Cal Water notifies owners when its survey shows a property needs protection, and commercial service applicants fill out a backflow survey with their application. Failing to comply can lead to water service being shut off. We install and repair the assemblies these rules require; see backflow preventers.

Water heaters: hard groundwater and SVCE rebates

Cal Water blends local groundwater with treated surface water bought from Valley Water. Its 2025 water quality report lists groundwater hardness averaging 305 ppm (137–440 ppm), which the report’s own scale calls very hard, against 97 ppm for the Valley Water supply. Hard water builds scale in tanks, tankless heat exchangers and fixtures, so flushing and descaling matter more here. Los Altos buys its electricity through Silicon Valley Clean Energy, whose business rebates cover commercial heat pump water heaters of 81 gallons or more that replace gas or electric resistance units. The site needs an active commercial SVCE account, the reservation must come before installation, and the claim needs proof of permitting. The City’s own extra heat pump rebates are for homes only. See commercial water heaters.

Sources

City of Los Altos: Sewer lateral responsibility · Sewer maintenance FAQs · Maintenance and Services · How to prevent sanitary sewer backups · Building · Permit submittal process · Building forms and handouts · Heat pump rebates · Municipal Code ch. 10.04 · Municipal Code ch. 10.08. City of Palo Alto: Regional Water Quality Control Plant. Cal Water: Los Altos Suburban district · 2025 water quality report · Cross-connection control · Commercial service application and backflow survey. Silicon Valley Clean Energy: Business rebate equipment specifications. Checked October 2026.