Non-Transient Non-Community · PWSID CA0706028

Knightsen Elementary School

Serves 350 peopleGroundwaterOwner: Local GovernmentKnightsen, CaliforniaServes a school or daycare
Nothing open right now.

On record since 2009: 13 violations. 13 over the limit. Most recent began 2016-10-01.

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

13Over the limit
0Treatment lapse
0Missed or late test
0Notice or report

More violations on record than 90% 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

20052009 · Over the limit: 120102014 · Over the limit: 42014 · Over the limit: 42014 · Over the limit: 42014 · Over the limit: 42015 · Over the limit: 42015 · Over the limit: 42015 · Over the limit: 42015 · Over the limit: 420152016 · Over the limit: 42016 · Over the limit: 42016 · Over the limit: 42016 · Over the limit: 420202025
One square = one violation, by the year it began. Empty columns are years with nothing on EPA's record.
100% over the limit · 13

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×+Arsenic2014-04-01 · Arsenic: measured 0.0120 MG/L vs limit 0.0100 MG/L (1.2×)2009-07-01 · Arsenic: measured 0.0120 MG/L vs limit 0.0100 MG/L (1.2×)
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

8.9 ppb
0 ppb

Every violation on record

  1. 2016-10-01ArsenicMCL, Averagemeasured 0.0120 MG/LBack in compliance
  2. 2016-07-01ArsenicMCL, Averagemeasured 0.0120 MG/LBack in compliance
  3. 2016-04-01ArsenicMCL, Averagemeasured 0.0120 MG/LBack in compliance
  4. 2016-01-01ArsenicMCL, Averagemeasured 0.0120 MG/LBack in compliance
  5. 2015-10-01ArsenicMCL, Averagemeasured 0.0130 MG/LBack in compliance
  6. 2015-07-01ArsenicMCL, Averagemeasured 0.0130 MG/LBack in compliance
  7. 2015-04-01ArsenicMCL, Averagemeasured 0.0130 MG/LBack in compliance
  8. 2015-01-01ArsenicMCL, Averagemeasured 0.0130 MG/LBack in compliance
  9. 2014-10-01ArsenicMCL, Averagemeasured 0.0127 MG/LBack in compliance
  10. 2014-07-01ArsenicMCL, Averagemeasured 0.0130 MG/LBack in compliance
  11. 2014-04-01ArsenicMCL, Averagemeasured 0.0120 MG/L · limit 0.0100 MG/LBack in compliance
  12. 2014-01-01ArsenicMCL, Averagemeasured 0.0132 MG/LBack in compliance
  13. 2009-07-01ArsenicMCL, Averagemeasured 0.0120 MG/L · limit 0.0100 MG/LBack in compliance

System details

Population served350
Service connections4
Water sourceGroundwater
System typeNon-Transient Non-Community
OwnerLocal Government
StatusActive
CityKnightsen
EPA ZIP on file94548

Areas served

  • Contra Costa County

Reading this record

Knightsen Elementary School is a non-transient non-community that draws from groundwater and serves about 350 people in Knightsen, 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.