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Montgomery County, Pennsylvania — public water systems

At a glance

166 active public water systems are filed under Montgomery County, Pennsylvania in EPA's SDWIS records, together reporting 1,274,113 people served. The largest is Aqua Pa Main System, which reports serving 822,600 people. 38 are community water systems serving people where they live; the other 128 are non-community systems, such as schools, workplaces, campgrounds and gas stations with their own supply.

Dataset updated . Source: EPA SDWIS/ECHO, refreshed quarterly.

Active systems

166

Population served

1.3M

Community systems

38

Groundwater share

84.3%

How does Montgomery County compare with other Pennsylvania counties?

Montgomery County has the 13th-most active public water systems among the 99 counties listed for active Pennsylvania systems in EPA records; among the 71 with 3 or more systems, the median has 76. Its systems report 1,274,113 people served in total, the 3rd-largest county figure in the state and 10% of the statewide total. The average system here reports serving 7,675 people, about 4.4 times the Pennsylvania average of 1,741. Population figures are what each system reports; people served by more than one system, such as a wholesaler and the town that buys from it, are counted by each.

Where does Montgomery County's drinking water come from?

By primary water source, Montgomery County's active systems draw on groundwater (140, 84%), purchased surface water (20, 12%) and surface water (6, 3.6%). Overall, 84% rely mainly on groundwater (including purchased groundwater) and 16% on surface water, compared with 93% and 6.8% across Pennsylvania. Groundwater means the system draws its water from wells or springs fed by underground aquifers. The county's largest system, Aqua Pa Main System, draws primarily on surface water.

What kinds of water systems operate in Montgomery County?

Montgomery County's active systems break down as 38 community systems (23%), 31 non-transient non-community systems (19%) and 97 transient non-community systems (58%). 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. A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. EPA lists their owner types as private (69%), public/private partnership (20%), local government (9%) and federal government (1.2%).

The 50 largest water systems in Montgomery County

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Active public water systems in Montgomery County, Pennsylvania
#Water systemCountyPopulation servedTypeSource
1Aqua Pa Main SystemMontgomery822,600CommunitySurface water
2North Penn Water AuthorityMontgomery91,941CommunityPurchased surface water
3Pa American NorristownMontgomery88,885CommunitySurface water
4North Wales Water AuthorityMontgomery72,496CommunitySurface water
5Pottstown Borough Water AuthMontgomery36,000CommunitySurface water
6Horsham Water&Sewer AuthorityMontgomery26,000CommunityPurchased surface water
7Ambler Boro Water DeptMontgomery20,000CommunitySurface water
8Aqua Pa HatboroMontgomery12,901CommunityPurchased surface water
9Aqua Pa Superior Main SystemMontgomery11,400CommunityPurchased surface water
10Merck and Co Inc.Montgomery8,550Non-transient non-communityPurchased surface water
11Collegeville Trappe Joint PWDMontgomery8,470CommunityGroundwater
12Pa American AudubonMontgomery8,200CommunityPurchased surface water
13Telford Borough AuthorityMontgomery7,700CommunityPurchased surface water
14Schwenksville Borough AuthMontgomery5,200CommunityPurchased surface water
15Upper Hanover Water AuthorityMontgomery4,600CommunityGroundwater
16Aqua Pa Perkiomen TownshipMontgomery3,600CommunityGroundwater
17Radisson Valley Forge HotelMontgomery3,500Non-transient non-communityGroundwater
18E Greenville Boro Water DeptMontgomery3,100CommunitySurface water
19Red Hill Water AuthorityMontgomery2,500CommunityGroundwater
20Valley Forge Natl ParkMontgomery2,300Transient non-communityGroundwater
21Hatfield Quality Meats Inc.Montgomery1,850Non-transient non-communityGroundwater
22Constellation Nuclear Pwr PlntMontgomery1,650Non-transient non-communityGroundwater
23Upper Dublin High SchoolMontgomery1,473Non-transient non-communityPurchased surface water
24Pottstown Hosp Tower HealthMontgomery1,425Non-transient non-communityPurchased surface water
25Village of Neshaminy FallsMontgomery1,300CommunityPurchased surface water
26Parkhouse Nursing & Rehab CtrMontgomery1,200CommunityGroundwater
27Aqua Pa Perkiomen WoodsMontgomery1,100CommunityGroundwater
28Spring Mountain AdventuresMontgomery1,000Transient non-communityGroundwater
29New Hanover Upper Fred E SMontgomery850Non-transient non-communityGroundwater
30Aqua Pa Upper ProvidenceMontgomery810CommunityPurchased surface water
31Marlborough Elementary SchoolMontgomery800Non-transient non-communityGroundwater
32Gilbertsville ElementaryMontgomery800Non-transient non-communityGroundwater
33Jefferson Hospital LansdaleMontgomery700Non-transient non-communityPurchased surface water
34Frederick LivingMontgomery640CommunityGroundwater
35Camp Hart Musser ReservationMontgomery600Transient non-communityGroundwater
36Fort Washington Elem SchoolMontgomery532Non-transient non-communityPurchased surface water
37Perkiomen CrossingMontgomery508CommunityGroundwater
38Hickory Valley G C Snack BarMontgomery500Transient non-communityGroundwater
39Salford Hills Elem SchoolMontgomery500Non-transient non-communityGroundwater
40Aqua Pa Superior Center PointMontgomery500CommunityGroundwater
41Horsham ClinicMontgomery488Non-transient non-communityGroundwater
42Biddle Air National Guard BaseMontgomery440Non-transient non-communityGroundwater
43Camp Hope for KidsMontgomery410Transient non-communityGroundwater
44Limerick DinerMontgomery400Transient non-communityGroundwater
45Indian Valley Country ClubMontgomery400Transient non-communityGroundwater
46Flourtown Swim ClubMontgomery350Transient non-communityGroundwater
47Camp Green LaneMontgomery350Transient non-communityGroundwater
48Lehigh Valley Dairies NtncMontgomery328Non-transient non-communityGroundwater
49Green Hill MHPMontgomery323CommunityGroundwater
50Avante ApartmentsMontgomery315CommunityGroundwater

All other water systems in Montgomery County (116)

The remaining active systems filed under Montgomery County, largest first, with the population each reports serving.

Montgomery County water systems: frequently asked questions

How many public water systems are in Montgomery County, Pennsylvania?

EPA's SDWIS records file 166 active public water systems under Montgomery County, Pennsylvania: 38 community systems (23%), 31 non-transient non-community systems (19%) and 97 transient non-community systems (58%).

Who supplies drinking water in Montgomery County, PA?

The largest community water systems filed under Montgomery County are Aqua Pa Main System (822,600 people served), North Penn Water Authority (91,941 people served) and Pa American Norristown (88,885 people served). Which system serves a particular address depends on its service area, which EPA's SDWIS records do not include; a water bill or the local utility can confirm it.

Does Montgomery County's drinking water come from groundwater or surface water?

Of the 166 active public water systems in Montgomery County, 84% draw mainly on groundwater and 16% on surface water, counting purchased supplies. The largest system, Aqua Pa Main System, uses surface water.

Where can I find a water quality report for Montgomery County?

Each community water system must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1, covering the previous calendar year. 38 community systems are filed under Montgomery County, so the report to look for is the one from the system that supplies your address.

How can I check violations for a water system in Montgomery County?

Open the system's profile from the list on this page. Each profile shows the most recent Safe Drinking Water Act violations in EPA's records, with plain-English labels and whether each one is resolved. For current compliance status, EPA ECHO is the primary source.

More Pennsylvania water systems

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, “Public water systems in Montgomery County, Pennsylvania”, https://aquacensus.com/water-systems/pennsylvania/montgomery (data as of October 1, 2026).