San Pasqual, CA tap water
Supplied mostly by Cal/Am Water Company - San Marino, plus 1 other utility. Here's what the water means for your fish.
Disinfectant
Chloramine
Your water is treated with chloramine. Unlike chlorine, it doesn't gas off when water sits out, and many pitcher and fridge filters aren't rated to remove it. Conditioners that list chloramine on the label break it apart, which frees about 0.34 ppm of ammonia here. Some utilities switch to plain chlorine for a few weeks a year.
Safety for fish and shrimp
Ammonia (with conditioner)
Estimate0.34–0.73 ppm (Low)
Typical 0.34 ppm
This is what a conditioner frees when it breaks the chloramine apart. A cycled filter clears it within a day.
Estimated from the chloramine level Pasadena Water and Power (PWP) reports (2024).
Nitrite (NO₂)
Not detected (Low)
Not detected in testing, so any nitrite in your tank comes from the tank itself.
From EPA monitoring data; California Water Board lab results (2014–2023).
Nitrate (NO₃)
15–28 ppm (Worth knowing)
Typical 15 ppm
Water changes can't take your tank's nitrate below this level.
From California Water Board lab results; Pasadena Water and Power (PWP)'s 2024 water quality report (2023–2026).
Copper at home taps
0.06–0.26 ppm (Low)
Typical 0.06 ppm
Low. Water that sits in household pipes overnight can carry more than this.
From California Water Board lab results; Pasadena Water and Power (PWP)'s 2024 water quality report (2023–2024).
Chlorine or chloramine at the tap
1.4–3 ppm
Typical 1.4 ppm
At tap levels, chlorine and chloramine are toxic to fish, shrimp and the bacteria in a filter. Water conditioners are made for this range.
Published by your utility: Pasadena Water and Power (PWP)'s 2024 water quality report.
Water chemistry
General hardness
Supplier's figure82–303 ppm
Typical 218 ppm
Hard. Ideal for livebearers and African cichlids. Soft-water species may struggle to breed.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal. and Sierra Madre-City, Water Dept., which supplies Cal/Am Water Company - San Marino; Pasadena Water and Power (PWP)'s 2024 water quality report (2023–2026).
Carbonate hardness (alkalinity)
Supplier's figure68–210 ppm
Typical 128 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal. and Sierra Madre-City, Water Dept., which supplies Cal/Am Water Company - San Marino; Pasadena Water and Power (PWP)'s 2024 water quality report (2023–2026).
pH
7.1–8.2
Typical 8
Most community fish do well here. Stable water matters more than the exact number.
From EPA monitoring data; Pasadena Water and Power (PWP)'s 2024 water quality report (2014–2024).
Total dissolved solids
Supplier's figure195–690 ppm
Typical 452 ppm
A rough measure of everything dissolved in the water. RO water reads near 0, so TDS is a quick way to compare waters.
From the utility that supplies yours: Metropolitan Water Dist. of So. Cal. and Sierra Madre-City, Water Dept., which supplies Cal/Am Water Company - San Marino; Pasadena Water and Power (PWP)'s 2024 water quality report (2023–2026).
Who supplies San Pasqual, CA
Cal/Am Water Company - San Marino
Serves 75% of residents · Buys water from Metropolitan Water Dist. of So. Cal. · Chloramine
- 2024 water quality report
Pasadena Water and Power (PWP)
Serves 6% of residents · Buys water from Metropolitan Water Dist. of So. Cal. · Chloramine
Our data comes from public records and is still incomplete. Many utilities don't publish every number, so we're adding more all the time. Your city's range is a starting point: testing your own tap is the only way to know exactly what's in it.
Tap water lookup covers US cities only for now. Want to know why it matters? Read our story on tap water.
Compiled by Shoal & Stem from public records. Free to cite with a link.