US Water Score: A
| Contaminant | Detected Level | EPA MCL | Health Guideline | Status |
|---|---|---|---|---|
| Lead |
18.0
|
15 ppb | 1 ppb | |
| Copper |
3440.0
|
1300 ppb | 300 ppb |
Water Quality Summary
Tap water quality in San Francisco, California (94105) receives an overall grade of A (Lower record-based concern) with a score of 100 out of 100, based on analysis of EPA compliance data, contaminant testing, and violation history. This is 8 points above the California state average of 92. Compared to the national average (75), this area performs significantly better. The area is served by 2 water systems providing water to approximately 848,019 people, using surface water and groundwater sources. The area has 27 violations over the past 5 years, though none were classified as health-based.
A score of 100/100 means public water-system records for San Francisco, CA show relatively few concerns in the US Water Score model. This is an internal score, not an EPA safety rating, and it does not guarantee conditions at any specific tap.
Health Information
Lead is a toxic metal that can leach from aging pipes and plumbing fixtures.
Even low levels of lead exposure can cause developmental delays in children, kidney damage, and cardiovascular effects in adults. The EPA action level is 15 ppb, but health experts recommend no safe level of lead in drinking water.
Lead enters water primarily through corrosion of lead service lines, lead solder, and brass fixtures — especially in homes built before 1986.
If lead is detected above 1 ppb, consider using a certified lead-removal filter (NSF/ANSI 53) for drinking and cooking water. Run cold water for 30 seconds before use if water has been sitting in pipes.
Copper can leach into water from copper plumbing, especially in newer homes or when water is acidic.
Short-term exposure above 1,300 ppb can cause gastrointestinal distress. Long-term exposure may cause liver or kidney damage. People with Wilson's disease are especially vulnerable.
Copper pipes, fittings, and faucets are the most common source. Corrosive (low-pH) water accelerates copper leaching.
If copper levels are elevated, flush pipes by running water for 15–30 seconds before use. Reverse osmosis and distillation systems effectively remove copper.
Common Questions
Based on public water-system records, San Francisco, California receives an internal US Water Score grade of A (Lower record-based concern) with a score of 100/100. This indicates relatively few system-level concerns in our model, but it is not an EPA safety rating and does not guarantee tap conditions inside individual homes.
ZIP code 94105 is served by 2 water systems using surface water, groundwater sources, providing water to approximately 848,019 people. Multiple source types mean your water may come from a blend of surface and underground sources.
Lead levels in the public-system record for San Francisco, California are 18.0 ppb, above the currently applicable EPA action level of 15 ppb. EPA's Lead and Copper Rule Improvements lower that action level to 10 ppb when the new requirements take effect. This system-level result does not measure an individual tap; consider a certified lead-removal filter and independent tap testing.
No PFAS ("forever chemicals") were detected in water systems serving San Francisco, California during the most recent EPA monitoring period (UCMR5). However, not all water systems have been tested for all PFAS compounds, and new contamination can occur over time.
Water systems serving San Francisco, California have received 27 violations in the last 5 years. Violations can range from paperwork issues (monitoring & reporting) to serious health-based violations where contaminant levels exceeded safe limits. Review the violation details above for specifics.
Based on detected contaminants (lead, copper), residents in San Francisco, California should consider: NSF/ANSI 53 certified filter — specifically rated for lead reduction. Pitcher filters (like Brita Longlast or PUR) and under-sink systems both work. Always look for filters with NSF/ANSI certification for the specific contaminants you want to remove.
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