Public water system · NY5903436

Active

Montrose Improvement District

At a glance

Montrose Improvement District (PWSID NY5903436) is an active community water system in Westchester County, New York. It reports serving 3,100 people through 850 service connections. Its primary water source is purchased surface water, and EPA lists it as owned by a local government. EPA's records list 10 violations for this system; 4 are health-based, and the most recent began in April 2023.

Dataset updated October 2026 . Source: EPA SDWIS/ECHO public records.

Population served

3,100

Service connections

850

Primary source

SWP

Purchased surface water

System type

CWS

Community water system

System record

PWSIDNY5903436

System typeCommunity water system

Activity statusActive

Population served3,100

Service connections850

Primary water sourcePurchased surface water

Owner typeLocal government

Primacy agencyNY state drinking water program

City servedCortlandt (T)

StateNew York

ZIP—

CountyWestchester County

How does Montrose Improvement District compare with other water systems in Westchester County?

By EPA's size categories, Montrose Improvement District is a small system (501 to 3,300 people). Westchester County has 273 active public water systems. Its population served is about 19% below the county average of 3,808 people per system, and accounts for 0.3% of the 1,039,556 people reported by systems filed under the county. Across New York, the 8,167 active systems average 2,374 people each. Nationally, the average active community water system reports serving 6,703 people, so Montrose Improvement District is about half of that figure.

What does “community water system” mean?

A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. New York has 2,281 active community water systems, 28% of the state's 8,167 active systems. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 399 New York systems (4.9%) list purchased surface water as their primary source.

Who owns and regulates Montrose Improvement District?

EPA lists Montrose Improvement District as owned by a local government. The NY state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 77 of the 273 active systems in Westchester County (28%) are also owned by a local government.

Does Montrose Improvement District have drinking water violations?

EPA's records list 10 violations for this system; 4 are health-based, and the most recent began in April 2023. The violations listed here began between January 1992 and April 2023. By type: 6 monitoring and reporting and 4 required treatment not met. The contaminant or rule involved most often is Surface Water Treatment Rule (4 of them). EPA lists 6 as resolved and 4 as archived. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.

Began	Violation	Contaminant or rule	Health-based	Status
2023-04-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Haloacetic acids (HAA5)code 2456	No	Archived
2023-04-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Total trihalomethanes (TTHM)code 2950	No	Archived
2022-04-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Total trihalomethanes (TTHM)code 2950	No	Archived
2022-04-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Haloacetic acids (HAA5)code 2456	No	Archived
2012-10-01	Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24	Total coliform bacteria (TCR)code 3100	No	Resolved
2008-07-01	Monitoring and reportingMonitoring, Regular · code 03	Nitratecode 1040	No	Resolved
1994-03-01	Required treatment not metTreatment Technique (SWTR and GWR) · code 41	Surface Water Treatment Rulecode 0200	Yes	Resolved
1994-02-01	Required treatment not metTreatment Technique (SWTR and GWR) · code 41	Surface Water Treatment Rulecode 0200	Yes	Resolved
1993-12-01	Required treatment not metTreatment Technique (SWTR and GWR) · code 41	Surface Water Treatment Rulecode 0200	Yes	Resolved
1992-01-01	Required treatment not metFailure to Filter (SWTR) · code 42	Surface Water Treatment Rulecode 0200	Yes	Resolved

All 10 violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.

Montrose Improvement District: frequently asked questions

Who runs Montrose Improvement District?

Montrose Improvement District (PWSID NY5903436) is a community water system owned by a local government. It is regulated by the NY state drinking water program.

How many people does Montrose Improvement District serve?

Montrose Improvement District reports serving 3,100 people through 850 service connections in Westchester County, New York.

Where does Montrose Improvement District get its water?

EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.

Does Montrose Improvement District have any drinking water violations?

EPA's records list 10 violations for this system; 4 are health-based, and the most recent began in April 2023. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.

Is Montrose Improvement District's water safe to drink?

AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. EPA's records list 10 violations for this system; 4 are health-based, and the most recent began in April 2023. For current results, consult the system's annual water quality report, EPA ECHO, or the NY state drinking water program.

Where can I find Montrose Improvement District's water quality report?

As a community water system, Montrose Improvement District must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.

Other water systems in Westchester County

Water system	County	Population served	Type	Source
Yonkers City	Westchester	211,569	Community	Purchased surface water
Veolia Water New York, Inc.. Rd-1	Westchester	146,732	Community	Purchased surface water
Greenburgh Consolidated Wd #1	Westchester	86,624	Community	Purchased surface water
Mount Vernon Water Department	Westchester	73,893	Community	Purchased surface water
Westchester Joint Water Works	Westchester	59,629	Community	Surface water
White Plains City	Westchester	59,559	Community	Purchased surface water

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About this data

Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.

Cite as: AquaCensus, “Montrose Improvement District, PWSID NY5903436, New York”, https://aquacensus.com/water-systems/new-york/montrose-improvement-district-ny5903436 (data as of October 1, 2026).