Pittsburg, CA tap water
Supplied mostly by City of Pittsburg, 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 a little ammonia. Some utilities switch to plain chlorine for a few weeks a year.
Safety for fish and shrimp
Ammonia
Up to 1.58 ppm (Low)
Typical 0.23 ppm
Ammonia in the water as delivered. A cycled filter clears it within a day.
From California Water Board lab results; the chloramine level Contra Costa Water District reports; Contra Costa Water District's 2025 water quality report (2024–2026).
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 (2023–2026).
Nitrate (NO₃)
Up to 3.5 ppm (Low)
Typical 1 ppm
Low, so water changes lower your tank's nitrate well.
From California Water Board lab results; Contra Costa Water District's 2025 water quality report (2023–2026).
Copper at home taps
Up to 0.11 ppm (Low)
Typically not detected
Not detected in testing. Water that sits in household pipes overnight can still pick some up.
From California Water Board lab results; Contra Costa Water District's 2025 water quality report (2024–2025).
Chlorine or chloramine at the tap
0–3.5 ppm
Typical 1.8 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: Contra Costa Water District's 2025 water quality report.
Water chemistry
General hardness
53–116 ppm
Typical 60 ppm
Soft. Good for tetras, rasboras and most shrimp. Livebearers, snails and African cichlids prefer harder water.
From California Water Board lab results; Contra Costa Water District's 2025 water quality report (2024–2025).
Carbonate hardness (alkalinity)
44–82 ppm
Typical 62 ppm
Moderate buffering. pH should stay fairly steady.
From California Water Board lab results; Contra Costa Water District's 2025 water quality report (2023–2025).
pH
7.9–9
Typical 8.4
Alkaline. Many utilities raise pH to protect pipes. Stability matters more than the exact number.
From California Water Board lab results; Contra Costa Water District's 2025 water quality report (2023–2025).
Total dissolved solids
128–380 ppm
Typical 262 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 California Water Board lab results; Contra Costa Water District's 2025 water quality report (2023–2026).
- City of Pittsburg adds phosphate to protect pipes. It can feed algae in tanks without much plant growth.
Who supplies Pittsburg, CA
City of Pittsburg
Serves 50% of residents · Buys water from Contra Costa Water District · Chloramine
- 2025 water quality report
Contra Costa Water District
Serves 50% of residents · Lake or river water · 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.
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Compiled by Shoal & Stem from public records. Free to cite with a link.