Community Water System · PWSID NY5903435

Westchester Joint Water Works

Serves 59,629 peopleSurface WaterOwner: Local GovernmentMamaroneck, New York
1 open treatment violation.

Open for: Surface water treatment (SWTR). EPA counts treatment-technique violations as health-based: a required protective step was not done. It is not a measurement of contamination.

On record since 1993: 8 violations. 3 over the limit · 2 treatment lapses · 3 missed or late tests. Most recent began 2020-10-01.

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

3Over the limit
2Treatment lapse1 open
3Missed or late test
0Notice or report

More violations on record than 61% of active water systems in New York. Small systems with no staff chemist often rack up missed-test violations; big utilities rarely do.

The record, year by year

1993 · Treatment lapse: 11995200020052007 · Missed or late test: 12009 · Missed or late test: 120102015 · Treatment lapse: 120152019 · Over the limit: 32019 · Over the limit: 32019 · Over the limit: 32020 · Missed or late test: 120202025
One square = one violation, by the year it began. Empty columns are years with nothing on EPA's record.
38% over the limit · 325% treatment lapse · 238% missed or late test · 3

Across New York, 67% of violations are missed or late tests and 3% are water over a limit.

How far over the limit

at the limit2×5×10×100×+Total Haloacetic Acids (HAA5)2019-07-01 · Total Haloacetic Acids (HAA5): measured 0.0610 MG/L vs limit 0.0600 MG/L (1.0×)2019-04-01 · Total Haloacetic Acids (HAA5): measured 0.0610 MG/L vs limit 0.0600 MG/L (1.0×)2019-01-01 · Total Haloacetic Acids (HAA5): measured 0.0680 MG/L vs limit 0.0600 MG/L (1.1×)
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 9 results on file · action level 15 ppb

10.7 ppb
10.7 ppb
10.7 ppb
8.1 ppb
4.8 ppb
4.5 ppb
4.4 ppb
3.9 ppb
3.3 ppb

Open now (1)

  1. 1993-06-30Surface water treatment (SWTR)Failure to Filter (SWTR)Open

Every violation on record

  1. 2020-10-011,4-DioxaneMonitoring, RegularPeriod ended · no return to compliance on file
  2. 2019-07-01Total Haloacetic Acids (HAA5)MCL, Averagemeasured 0.0610 MG/L · limit 0.0600 MG/LBack in compliance
  3. 2019-04-01Total Haloacetic Acids (HAA5)MCL, Averagemeasured 0.0610 MG/L · limit 0.0600 MG/LBack in compliance
  4. 2019-01-01Total Haloacetic Acids (HAA5)MCL, Averagemeasured 0.0680 MG/L · limit 0.0600 MG/LBack in compliance
  5. 2015-05-01Surface water treatment (LT2)Failure to Filter (SWTR)Back in compliance
  6. 2009-01-01Lead and Copper RuleInitial, Follow-up, or Routine Source Water M/RBack in compliance
  7. 2007-10-01Lead and Copper RuleFollow-up Or Routine LCR Tap M/RBack in compliance
  8. 1993-06-30Surface water treatment (SWTR)Failure to Filter (SWTR)Open

System details

Population served59,629
Service connections12,000
Water sourceSurface Water
System typeCommunity Water System
OwnerLocal Government
StatusActive
CityMamaroneck
EPA ZIP on file10543

Areas served

  • Westchester County

Reading this record

Westchester Joint Water Works is a community water system that draws from surface water and serves about 59,629 people in Mamaroneck, New York. 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.