TapBuff
ZIP
Menu

Town of Discovery BayWater quality report

Serves
16,790
Connections
6,163
Water source
Groundwater
Based in
Discovery Bay, CA
County
Contra Costa
Owner
Local government
The ZIP code it serves

94505

PWSID CA0710009 · EPA data

Read this first

  • Lithium was found in four of 4 samples, highest 34 ppb. Above EPA’s health reference level of 10 ppb, a screening level rather than an enforceable limit.

No health-based violations on file since 2016.

What was found, stop by stop

  • Below the health goal
  • Above the health goal
  • Above the legal limit
  • No federal data

  1. At the source

    EPA UCMR 5 sampled this utility for 29 PFAS and lithium from Feb. 28, 2023 to Oct. 3, 2023. Each tick under a result’s line is one sample where it was found, dated when you point at it.

  2. Lithium

    Above EPA’s health benchmark

    34ppb

    Highest of 4 samples; found in four

    Above EPA’s health reference level of 10 ppb, a screening level rather than an enforceable limit.

    What handles it: No certification claim covers this compound yet.

  3. In treatment

    No federal results for this stop. Disinfection byproduct, chlorine and fluoride levels are in Town of Discovery Bay’s own annual report, which it must send you every year.

  4. In the pipes

    No lead and copper results on file with EPA for this utility.

  5. At your tap

    The last stretch is your own plumbing. A certified lab test is the only way to know what reaches your glass. Lead in your water: what to do

Tested and not found

Below EPA’s minimum reporting level in every sample taken from Feb. 28, 2023 to Oct. 3, 2023. Not found means not measured above that level, which is not the same as zero.

All 30 compounds tested and not found
  • 11Cl-PF3OUdS
  • 4:2 FTS
  • 6:2 FTS
  • 8:2 FTS
  • 9Cl-PF3ONS
  • ADONA
  • HFPO-DA (GenX)
  • Lead
  • NEtFOSAA
  • NFDHA
  • NMeFOSAA
  • PFBA
  • PFBS
  • PFDA
  • PFDoA
  • PFEESA
  • PFHpA
  • PFHpS
  • PFHxA
  • PFHxS
  • PFMBA
  • PFMPA
  • PFNA
  • PFOA
  • PFOS
  • PFPeA
  • PFPeS
  • PFTA
  • PFTrDA
  • PFUnA

Violations since 2016

No health-based violations on file with EPA since 2016.

What this report cannot tell you

  • Levels of everything else. Federal bulk data carries results for PFAS, lithium, lead and copper, and violations for the rest. Nitrate, arsenic, disinfection byproducts and other levels are in Town of Discovery Bay’s own annual report, which it must send you every year.
  • Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.
  • Anything after the latest data. SDWIS data is from 2026 Q2; UCMR 5 samples are from Feb. 28, 2023 to Oct. 3, 2023.

Other California utilities

All California utilities

Sources

What to do next

  1. About Lithium

    What each marked result does to health, where it comes from, and the certification claim that addresses it.

  2. Read the utility’s own report

    Town of Discovery Bay must send you a water quality report every year. It lists nitrate, arsenic and byproduct levels this page cannot.

  3. Test your own tap for lead

    Your service line, solder and fixtures decide the lead at your faucet, not the utility’s average.

  4. NSF/ANSI standards, decoded

    A filter for taste or chlorine is a preference, not a need. The standards say what each kind can do.