Commercial Plumber in South San Francisco, CA

A Property Manager’s Guide to Plumbing in South San Francisco

Two water providers, one City sewer system

Most of South San Francisco gets its water from California Water Service (Cal Water), whose South San Francisco system is part of its Bayshore District; its main and after-hours line is (650) 558-7800. The Westborough area is served by the Westborough Water District, which provides water and sewer service to about one square mile of the city. Its sewers are maintained under contract by Daly City’s North San Mateo County Sanitation District, and the District’s office number, 650-589-1435, forwards after-hours calls to on-call staff.

Elsewhere, the City’s Public Works Department maintains the sewer mains. Save its numbers with your building’s emergency contacts: (650) 877-8550 on weekdays and (650) 873-3333 (Police Communications, which dispatches the standby crew) for a sewer overflow after hours. Wastewater goes to the City’s Water Quality Control Plant on Belle Air Road, which provides secondary treatment for South San Francisco, San Bruno and Colma.

Sewer laterals and cleanouts

The property owner builds, cleans and maintains the lateral (Municipal Code §14.14.040). If there is a City-approved cleanout in the sidewalk, or in the right-of-way where there is no sidewalk, the City maintains the lateral from that cleanout to the main; otherwise the owner is responsible all the way to the City main, including the wye. The City allows one lateral per lot, including for commercial developments, unless an agreement waives it.

Cleanouts must be added at the owner’s expense on new construction, remodels of more than 25% of the building area, any lateral repair or replacement, when backflow protection or a relief device is installed, and on buildings with pumped sewage or floors below the main (§14.14.150). If an owner skips a required cleanout, the City is relieved of responsibility for later overflow damage.

Lateral certificates for commercial properties

Section 14.14.190 applies to commercial and industrial properties as well as homes. A certificate of compliance is required when any part of a lateral is repaired or replaced, when a new building applies for a certificate of occupancy, when a use changes to restaurant, commercial or industrial, and before a sale when a building on the property is more than 25 years old. Remodels of more than 25% of the building area need a certificate before the building permit is issued (§14.14.140).

The process: a licensed plumber records a CCTV video and fills out the City’s inspection form, and the owner emails the application, form and video to the Engineering Division, which allows 5–10 business days for review. The video must be an original color file showing the address, date and time, a running footage marker, the cleanout used, joints and the full lateral to the City main. Repairs need an encroachment permit from Engineering, plus a building permit for the upper lateral or a building cleanout. If a sale can’t wait, a 180-day extension is available with a refundable deposit. Properties in the Westborough Water District are handled by the District. See commercial sewer repair.

Restaurants: the plant’s grease rules

Food facilities apply to the Water Quality Control Plant for a food facility permit, listing their grease trap or interceptor size and cleaning frequency. Under §14.08.210:

• New, remodeled or converted commercial kitchens permitted since 2010 need a grease interceptor for each grease-generating activity, sized to the Uniform Plumbing Code, and no new garbage disposals.
• Pumping: at least every six months, and more often if needed.
• Records: a log of each removal (date, amount, disposal) kept on site for 3 years; the plant publishes a log sheet and a list of grease haulers.
• No additives: enzymes, emulsifiers and bacteria are prohibited; only mechanical cleaning is allowed.

Pumping handles the interceptor; scheduled hydro jetting keeps the kitchen lines leading to it open.

Labs, biotech and industrial discharges

The City counts more than 250 biotech companies among its 2,800 businesses, and its Environmental Compliance Program ((650) 829-3848) runs the pretreatment program. Significant industrial users need a wastewater discharge permit before discharging, applied for at least 90 days ahead, and every user must have approved protection against accidental discharges. The permit application covers activities such as bio-medical research, cage washing and pharmaceutical manufacturing, and asks about pretreatment such as pH adjustment. The local limits set pH between 5.0 and 12.0, along with limits for metals and solvents. Separate permits cover groundwater and construction dewatering discharges.

Backflow testing

Cal Water’s cross-connection program requires backflow assemblies to be inspected and tested every year by certified testers, and air gaps inspected annually. Property owners are responsible for the assemblies on their side of the meter; Cal Water notifies owners when a backflow survey shows protection is needed and can discontinue service until it’s in place. New commercial and industrial services submit a backflow survey with the service application. We install and repair the assemblies these rules require; see backflow preventers.

Permits for plumbing work

The Building Division issues permits through the City’s online permitting center, which handles over-the-counter permits such as water heaters. Plumbing work must be permitted even where other work is exempt. The counter is open weekdays 8 a.m. to 4 p.m. (closed noon to 1 p.m.), and the main line is (650) 829-6670, option 1. Work in the street or sidewalk needs an encroachment permit from the Engineering Division (650-829-6652), and Public Works inspections must be booked at least 24 hours ahead at (650) 829-6656.

Water heaters and water quality

Cal Water’s South San Francisco system blends water bought from the SFPUC with water from six local wells. In 2025 the well water measured 287–461 ppm hardness (average 384), very hard, while SFPUC water measured 8.1–112 ppm (average 62); Westborough’s water is all SFPUC. Where well water reaches a building, scale builds quickly in tanks, tankless heat exchangers and fixtures, so flushing and descaling matter more. For a move to heat pump water heaters, WestLight Energy (formerly Peninsula Clean Energy) offers businesses no-cost design and technical help. See commercial water heaters.

Sources

City of South San Francisco: Public Works · Report an issue · Maintenance & Operations · Water Quality Control Plant · Environmental Compliance · Food facility permit application · Industrial waste discharge permit application · Local discharge limits · Permits & Development · Sewer lateral fact sheet · Sewer lateral certificate application · Building Division · Plan submittal and permit requirements · Biotech in SSF · Municipal Code ch. 14.08 · Municipal Code ch. 14.14. Cal Water: 2025 water quality report, South San Francisco · Bayshore District · Cross-connection control · Commercial service application and backflow survey. Westborough Water District: Sanitary sewer · Emergency info · Water quality report. WestLight Energy: Electric buildings for business. Checked October 2026.