East Pasadena, CA tap water
Supplied mostly by Pasadena Water and Power (PWP), plus 3 other utilities. Here's what the water means for your fish.
Disinfectant
Chlorine or chloramine
Utilities here use chlorine or chloramine, depending on which one serves your address. Chlorine slowly gases off from standing water; chloramine doesn't.
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 California Water Board lab results; EPA monitoring data (2014–2023).
Nitrate (NO₃)
3.6–28 ppm (Worth knowing)
Typical 20 ppm
Water changes can't take your tank's nitrate below this level.
From Pasadena Water and Power (PWP)'s 2024 water quality report; EPA monitoring data; California Water Board lab results (2012–2026).
Copper at home taps (first draw)
0.05–0.26 ppm (Worth knowing)
The 90th percentile of first-draw samples from homes: water that sat in household pipes for at least six hours.
Shrimp and snails are sensitive to copper. Water that sits in household pipes picks up the most; it drops once the tap has run for a minute.
From Pasadena Water and Power (PWP)'s 2024 water quality report; California Water Board lab results (2023–2025).
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
59–303 ppm
Typical 236 ppm
Hard. Ideal for livebearers and African cichlids. Soft-water species may struggle to breed.
From Pasadena Water and Power (PWP)'s 2024 water quality report; California Water Board lab results, measured before treatment; Metropolitan Water Dist. of So. Cal. and Sierra Madre-City, Water Dept., which supplies Cal/Am Water Company - San Marino (2023–2026).
Carbonate hardness (alkalinity)
68–210 ppm
Typical 118 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From Pasadena Water and Power (PWP)'s 2024 water quality report; California Water Board lab results, measured before treatment; Metropolitan Water Dist. of So. Cal. and Sierra Madre-City, Water Dept., which supplies Cal/Am Water Company - San Marino; California Water Board lab results (2023–2026).
pH
6.5–8.2
Typical 7.3
Most community fish do well here. Stable water matters more than the exact number.
From Pasadena Water and Power (PWP)'s 2024 water quality report; California Water Board lab results, measured before treatment; EPA monitoring data (2014–2026).
Total dissolved solids
180–690 ppm
Typical 410 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 Pasadena Water and Power (PWP)'s 2024 water quality report; California Water Board lab results, measured before treatment; Metropolitan Water Dist. of So. Cal. and Sierra Madre-City, Water Dept., which supplies Cal/Am Water Company - San Marino; California Water Board lab results (2023–2026).
Who supplies East Pasadena, CA
- 2024 water quality report
Pasadena Water and Power (PWP)
Serves 61% of residents · Buys water from Metropolitan Water Dist. of So. Cal. · Chloramine
Cal-Am Water Company - East Pasadena
Serves 36% of residents · Groundwater (wells) · Chlorine
Cal/Am Water Company - San Marino
Serves 7% of residents · Buys water from Metropolitan Water Dist. of So. Cal. · Chloramine
Sunny Slope Water Co.
Serves 5% of residents · Groundwater (wells) · Chlorine
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.