Is San Lorenzo, CA tap water safe?

A town can be served by more than one utility, and some homes are on private wells. The name on your water bill tells you which is yours, and your ZIP code narrows it down. They are listed by how many people each serves in San Lorenzo’s ZIP codes, from EPA’s estimates.

• East Bay MUD

  California · serves 1.5 million people · about 23,900 in San Lorenzo

  1 result above the health goal. The worst: Uranium at 5.3 ppb, above the health goal. Hardness: soft to moderately hard depending on the source, 17 to 120 mg/L (1 to 7 grains per gallon).

  No health-based violations since 2016

  Open report

• City of Hayward

  California · serves 162,954 people · about 3,300 in San Lorenzo

  1 result above the health goal. The worst: Arsenic at 0.75 ppb, above the health goal. Hardness: hard to very hard depending on the source, 131 to 260 mg/L (7.7 to 15.2 grains per gallon).

  No health-based violations since 2016

  Open report

MUD stands for municipal utility district, a local water and sewer district common in Texas.

Which ZIP codes are in San Lorenzo: Census 2020 relationship files. Which utilities serve them, and how many people: EPA SDWIS and EPA’s service area map. Each utility’s results: EPA UCMR 5, EPA SDWIS, and EPA’s and the state’s compliance monitoring, as its report lists them. How they are measured: methodology. Certified labs: California State Water Resources Control Board, ELAP accredited laboratories and their fields of accreditation; distances from the Census 2020 ZIP code tabulation area gazetteer.