Chula Vista, CA tap water
Supplied mostly by Sweetwater Authority, 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)
Estimate0.05–1.12 ppm (Worth knowing)
Typical 0.71 ppm
This is what a conditioner frees when it breaks the chloramine apart. A cycled filter clears it within a day; a big water change in a new or very small tank adds more of it at once. Some conditioners also bind ammonia for a day or so.
Estimated from the chloramine level Sweetwater Authority reports (2025).
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 (2013–2026).
Nitrate (NO₃)
Up to 11 ppm (Low)
Typical 1 ppm
Low, so water changes lower your tank's nitrate well.
From Sweetwater Authority's 2025 water quality report; California Water Board lab results; Helix Water District and San Diego County Water Authority, which supplies Otay Water District; EPA monitoring data (2012–2026).
Copper at home taps
Up to 0.43 ppm (Low)
Typical 0.07 ppm
Low. Water that sits in household pipes overnight can carry more than this.
From Sweetwater Authority's 2025 water quality report; California Water Board lab results (2023–2026).
Chlorine or chloramine at the tap
0.2–4.6 ppm
Typical 2.9 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: Sweetwater Authority's 2025 water quality report.
Water chemistry
General hardness
53–300 ppm
Typical 206 ppm
Moderately hard. Great for livebearers, and most community fish adapt.
From Sweetwater Authority's 2025 water quality report; California Water Board lab results; Helix Water District and San Diego County Water Authority, which supplies Otay Water District (2023–2026).
Carbonate hardness (alkalinity)
41–390 ppm
Typical 119 ppm
Strong buffering. pH stays steady and hard to lower without RO water.
From Sweetwater Authority's 2025 water quality report; California Water Board lab results; Helix Water District and San Diego County Water Authority, which supplies Otay Water District (2023–2026).
pH
7.3–8.6
Typical 8
Most community fish do well here. Stable water matters more than the exact number.
From Sweetwater Authority's 2025 water quality report; California Water Board lab results; EPA monitoring data (2017–2026).
Total dissolved solids
340–6400 ppm
Typical 520 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 Sweetwater Authority's 2025 water quality report; California Water Board lab results; Helix Water District and San Diego County Water Authority, which supplies Otay Water District (2023–2026).
- Sweetwater Authority softens its water at the plant, so it may be softer than the local groundwater.
Who supplies Chula Vista, CA
- 2025 water quality report
Sweetwater Authority
Serves 42% of residents · Lake or river water · Chloramine
San Diego County Water Authority
Serves 26% of residents · Lake or river water · Chloramine
Otay Water District
Serves 25% of residents · Buys water from Helix Water District · Chloramine
Barona North
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.