San Diego, CA vs Bryn Mawr, PA

When comparing tap water quality between San Diego, CA and Bryn Mawr, PA, San Diego currently holds a noticeable 13-point lead in average WaterQ score, with a score of 85 out of 100 versus 72 for Bryn Mawr. San Diego, CA carries a B grade while Bryn Mawr, PA carries a C. A WaterQ score reflects an aggregate of EPA-reported violations, monitoring data, and compliance history across all public water systems serving each city, so a higher score generally indicates fewer recent violations and a stronger compliance record, though it does not guarantee that every tap in the city tests identically.

San Diego, CA is the larger of the two, with 456,159 more residents than Bryn Mawr. Bryn Mawr is served by 14 public water systems, compared with 6 in San Diego — a difference of 8 systems. A larger number of systems often reflects a more fragmented distribution network spanning multiple utilities, suburbs, or rural service areas, while a single large utility serving a big population can benefit from economies of scale in treatment and monitoring, but may also face more complex, aging infrastructure to maintain.

For residents of either San Diego or Bryn Mawr, the most useful next step is to look up the specific water system that serves your address, since city-wide averages combine results from every system in the area. Visit the San Diego or Bryn Mawr city pages below for a breakdown of local systems, recent violations, and contaminant-specific data, or browse WaterQ's contaminants directory to learn what each measured substance means for health.