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Oakland County, Michigan — public water systems

At a glance

734 active public water systems are filed under Oakland County, Michigan in EPA's SDWIS records, together reporting 1,145,905 people served. The largest is Troy, which reports serving 85,854 people. 105 are community water systems serving people where they live; the other 629 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

734

Population served

1.1M

Community systems

105

Groundwater share

95.2%

How does Oakland County compare with other Michigan counties?

Oakland County has the most active public water systems among the 131 counties listed for active Michigan systems in EPA records; among the 88 with 3 or more systems, the median has 92. Its systems report 1,145,905 people served in total, the 2nd-largest county figure in the state and 13% of the statewide total. The average system here reports serving 1,561 people, about 84% above the Michigan average of 847. 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 Oakland County's drinking water come from?

By primary water source, Oakland County's active systems draw on groundwater (699, 95%) and purchased surface water (35, 4.8%). Overall, 95% rely mainly on groundwater (including purchased groundwater) and 4.8% on surface water, compared with 97% and 3.1% across Michigan. Groundwater means the system draws its water from wells or springs fed by underground aquifers. The county's largest system, Troy, draws primarily on purchased surface water.

What kinds of water systems operate in Oakland County?

Oakland County's active systems break down as 105 community systems (14%), 125 non-transient non-community systems (17%) and 504 transient non-community systems (69%). 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 (87%), local government (7.6%) and state government (5.4%).

The 50 largest water systems in Oakland County

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Active public water systems in Oakland County, Michigan
#Water systemCountyPopulation servedTypeSource
1TroyOakland85,854CommunityPurchased surface water
2Rochester HillsOakland74,000CommunityPurchased surface water
3Waterford TownshipOakland73,441CommunityGroundwater
4SouthfieldOakland71,739CommunityPurchased surface water
5PontiacOakland63,776CommunityPurchased surface water
6Royal Oak, City ofOakland57,236CommunityPurchased surface water
7Farmington Hills, City ofOakland56,984CommunityPurchased surface water
8Novi, City ofOakland56,780CommunityPurchased surface water
9West Bloomfield TownshipOakland49,479CommunityPurchased surface water
10Bloomfield TownshipOakland41,691CommunityPurchased surface water
11Orion TownshipOakland33,000CommunityPurchased surface water
12Madison HeightsOakland29,694CommunityPurchased surface water
13Oak ParkOakland29,654CommunityPurchased surface water
14FerndaleOakland22,105CommunityPurchased surface water
15Auburn HillsOakland21,412CommunityPurchased surface water
16BirminghamOakland20,472CommunityPurchased surface water
17Commerce TownshipOakland19,811CommunityPurchased surface water
18Hazel ParkOakland16,400CommunityPurchased surface water
19BerkleyOakland14,970CommunityPurchased surface water
20Wixom, City ofOakland13,928CommunityPurchased surface water
21ClawsonOakland11,825CommunityPurchased surface water
22Independence TownshipOakland11,790CommunityGroundwater
23Farmington, City ofOakland11,597CommunityPurchased surface water
24South Lyon, City ofOakland11,055CommunityGroundwater
25Beverly HillsOakland10,451CommunityPurchased surface water
26Oxford TownshipOakland10,407CommunityGroundwater
27Lyon TownshipOakland9,390CommunityGroundwater
28Holly, Village ofOakland8,557CommunityGroundwater
29RochesterOakland7,130CommunityGroundwater
30White Lake TownshipOakland6,619CommunityGroundwater
31Milford, Village ofOakland6,366CommunityGroundwater
32Huntington WoodsOakland6,200CommunityPurchased surface water
33Gm Proving Grounds Well 5, 7, 8, 9Oakland5,500Non-transient non-communityGroundwater
34Walled Lake, City ofOakland5,260CommunityPurchased surface water
35Rochester EastOakland5,100CommunityPurchased surface water
36Southwest Oakland TownshipOakland4,943CommunityGroundwater
37Lathrup VillageOakland4,075CommunityPurchased surface water
38Highland TownshipOakland3,837CommunityGroundwater
39Bloomfield HillsOakland3,579CommunityPurchased surface water
40Oxford, Village ofOakland3,540CommunityGroundwater
41Kensington Water ParkOakland3,325Transient non-communityGroundwater
42Springs/Portsmouth ApartmentsOakland3,200CommunityGroundwater
43Lake Orion, Village ofOakland2,973CommunityPurchased surface water
44Pleasant RidgeOakland2,872CommunityPurchased surface water
45Keego Harbor, City ofOakland2,740CommunityPurchased surface water
46Highland Greens EstatesOakland2,268CommunityGroundwater
47Orchard Lake VillageOakland2,194CommunityPurchased surface water
48Sylvan LakeOakland2,155CommunityPurchased surface water
49Southeast Oakland TownshipOakland1,923CommunityGroundwater
50Royal Oak TownshipOakland1,869CommunityPurchased surface water

All other water systems in Oakland County (683)

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

Oakland County water systems: frequently asked questions

How many public water systems are in Oakland County, Michigan?

EPA's SDWIS records file 734 active public water systems under Oakland County, Michigan: 105 community systems (14%), 125 non-transient non-community systems (17%) and 504 transient non-community systems (69%).

Who supplies drinking water in Oakland County, MI?

The largest community water systems filed under Oakland County are Troy (85,854 people served), Rochester Hills (74,000 people served) and Waterford Township (73,441 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 Oakland County's drinking water come from groundwater or surface water?

Of the 734 active public water systems in Oakland County, 95% draw mainly on groundwater and 4.8% on surface water, counting purchased supplies. The largest system, Troy, uses purchased surface water.

Where can I find a water quality report for Oakland 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. 105 community systems are filed under Oakland 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 Oakland 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 Michigan 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 Oakland County, Michigan”, https://aquacensus.com/water-systems/michigan/oakland (data as of October 1, 2026).