Community Water System · PWSID CA3400138

Locke Water Works Co [Sws]

Serves 80 peopleGroundwaterOwner: PrivateWalnut Grove, California
Nothing open that measures the water, but 2 open testing or paperwork violations.

A missed test is not evidence of bad water. It also is not evidence of good water: for that period nobody checked.

On record since 1993: 15 violations. 8 over the limit · 3 missed or late tests · 4 notices or reports. Most recent began 2024-10-01.

For this year's test results, ask the utility for its annual Consumer Confidence Report. Every community system must publish one.

8Over the limit
0Treatment lapse
3Missed or late test2 open
4Notice or report

More violations on record than 91% of active water systems in California. Small systems with no staff chemist often rack up missed-test violations; big utilities rarely do.

The record, year by year

1993 · Missed or late test: 11995200020052009 · Notice or report: 12010 · Notice or report: 120102013 · Notice or report: 12015 · Notice or report: 120152016 · Over the limit: 42016 · Over the limit: 42016 · Over the limit: 42016 · Over the limit: 42017 · Over the limit: 32017 · Over the limit: 32017 · Over the limit: 32017 · Missed or late test: 120202021 · Over the limit: 12024 · Missed or late test: 12025
One square = one violation, by the year it began. Empty columns are years with nothing on EPA's record.
53% over the limit · 820% missed or late test · 327% notice or report · 4

Across California, 52% of violations are missed or late tests and 29% are water over a limit.

How far over the limit

at the limit2×5×10×100×+Arsenic2021-01-01 · Arsenic: measured 0.0310 UG/L vs limit 0.0100 UG/L (3.1×)2017-10-01 · Arsenic: measured 0.0243 UG/L vs limit 0.005000 UG/L (4.9×)2017-07-01 · Arsenic: measured 25.00 UG/L vs limit 10.00 UG/L (2.5×)2017-01-01 · Arsenic: measured 0.0137 MG/L vs limit 0.0100 MG/L (1.4×)2016-10-01 · Arsenic: measured 0.0210 MG/L vs limit 0.0100 MG/L (2.1×)2016-07-01 · Arsenic: measured 0.0210 MG/L vs limit 0.0100 MG/L (2.1×)2016-04-01 · Arsenic: measured 0.0280 MG/L vs limit 0.0100 MG/L (2.8×)2016-01-01 · Arsenic: measured 0.0297 MG/L vs limit 0.0100 MG/L (3.0×)
Each dot is one over-the-limit violation: the measured value divided by the limit it broke, on a log scale. Most legal limits for chemicals are running averages set for a lifetime of drinking, so “just over” and “ten times over” are very different news. Hover a dot for the numbers.

Lead & copper at the tap

Utilities sample taps in homes most likely to have lead pipes, and report the 90th-percentile result: 9 in 10 homes sampled came in at or below this number. Above the red line (the action level) the utility must act. The action level is not a safe level; EPA's health goal for lead is zero. EPA's file does not date these results, so they are shown highest first.

Lead, 90th percentile 2 results on file · action level 15 ppb

0 ppb
0 ppb

Open now (2)

  1. 2024-10-01Lead and Copper RuleFollow-up Or Routine LCR Tap M/ROpen
  2. 2017-10-01Lead and Copper RuleFollow-up Or Routine LCR Tap M/ROpen

Every violation on record

  1. 2024-10-01Lead and Copper RuleFollow-up Or Routine LCR Tap M/ROpen
  2. 2021-01-01ArsenicMCL, Averagemeasured 0.0310 UG/L · limit 0.0100 UG/LPeriod ended · no return to compliance on file
  3. 2017-10-01Lead and Copper RuleFollow-up Or Routine LCR Tap M/ROpen
  4. 2017-10-01ArsenicMCL, Averagemeasured 0.0243 UG/L · limit 0.005000 UG/LPeriod ended · no return to compliance on file
  5. 2017-07-01ArsenicMCL, Averagemeasured 25.00 UG/L · limit 10.00 UG/LPeriod ended · no return to compliance on file
  6. 2017-01-01ArsenicMCL, Averagemeasured 0.0137 MG/L · limit 0.0100 MG/LPeriod ended · no return to compliance on file
  7. 2016-10-01ArsenicMCL, Averagemeasured 0.0210 MG/L · limit 0.0100 MG/LPeriod ended · no return to compliance on file
  8. 2016-07-01ArsenicMCL, Averagemeasured 0.0210 MG/L · limit 0.0100 MG/LPeriod ended · no return to compliance on file
  9. 2016-04-01ArsenicMCL, Averagemeasured 0.0280 MG/L · limit 0.0100 MG/LPeriod ended · no return to compliance on file
  10. 2016-01-01ArsenicMCL, Averagemeasured 0.0297 MG/L · limit 0.0100 MG/LPeriod ended · no return to compliance on file
  11. 2015-07-01Consumer Confidence RuleCCR Complete Failure to ReportBack in compliance
  12. 2013-07-01Consumer Confidence RuleCCR Complete Failure to ReportBack in compliance
  13. 2010-07-01Consumer Confidence RuleCCR Inadequate ReportingBack in compliance
  14. 2009-07-01Consumer Confidence RuleCCR Complete Failure to ReportBack in compliance
  15. 1993-07-01Lead and Copper RuleInitial Tap Sampling for Pb and CuBack in compliance

System details

Population served80
Service connections44
Water sourceGroundwater
System typeCommunity Water System
OwnerPrivate
StatusActive
CityWalnut Grove
EPA ZIP on file95690

Areas served

  • Sacramento County

Reading this record

Locke Water Works Co [Sws] is a community water system that draws from groundwater and serves about 80 people in Walnut Grove, California. Everything above comes from the EPA's Safe Drinking Water Information System (SDWIS), where states report every violation by every public water system.

Four kinds of violation. Only one is a measurement of the water: over the limit means a test came back above a legal maximum (an MCL). A treatment lapse means a required protective step was not done, such as disinfection, filtration, fixing a defect an inspector found, or filing a lead-pipe inventory. A missed or late test means a required test was skipped or never reported. That is the most common kind, and the most misread: it does not mean the water was bad, and it does not mean the water was fine. Notices and reports covers public notices and the annual Consumer Confidence Report.

Status. “Back in compliance” means the state recorded a return to compliance. “Period ended” means the violation's compliance period is over but no return to compliance was ever filed, which is common in older records. EPA's federal copy lags state records by months, so call the utility for anything current.