New Jersey
Mercer County drinking water quality
99 active public water systems serve 324,154 people in Mercer County. 30 are compliant, 69 had at least one EPA violation in the past three years, 4 are designated serious violators, and 5 carry a health flag.
Active systems
99
11 community systems
People served
324K
by public water systems
Systems with violations
69
70% of active systems, past 3 years
Serious violators
4
5 systems carry a health flag
Needs attention
Washington Cross SP Green Grove Pic Area
NJ1106329 · Hopewell Twp.1106- · Transient non-community system · Serves 720
2 rules violated in the past three years
Bear Tavern School
NJ1106316 · Hopewell Twp.1106- · Non-Transient non-community system · Serves 555
5 rules violated in the past three years. Unresolved: Lead and Copper Rule.
Eden Autism Clayton Center
NJ1113307 · West Windsor Twp · Non-Transient non-community system · Serves 60
8 rules violated in the past three years. Unresolved: Lead and Copper Rule and Public Notice Rule and Revised PN Rule.
Lukoil Station #57703
NJ1106385 · Hopewell Twp.1106- · Transient non-community system · Serves 55
2 rules violated in the past three years. Unresolved: Revised Total Coliform Rule and Ground Water Rule.
Trenton Water Works
NJ1111001 · Ewing Twp, Hamilton Twp, Hopewell Twp.1106- and 2 more · Community water system · Serves 217,000
8 rules violated in the past three years. Unresolved: Lead and Copper Rule and Public Notice Rule and Revised PN Rule.
Stacys Cream King
NJ1108300 · Pennington Boro · Transient non-community system · Serves 400
3 rules violated in the past three years. Unresolved: Revised Total Coliform Rule and Ground Water Rule.
Professor's Hard Cider
NJ1112306 · Washington Twp · Transient non-community system · Serves 162
1 rule violated in the past three years. Unresolved: Revised Total Coliform Rule.
Hopewell Munic Services
NJ1106357 · Hopewell Twp.1106- · Non-Transient non-community system · Serves 95
2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Hopewell Township Municipal GA
NJ1106373 · Hopewell Twp.1106- · Transient non-community system · Serves 45
1 rule violated in the past three years. Unresolved: Revised Total Coliform Rule.
Community water systems
11 systems, largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Trenton Water Works Ewing Twp, Hamilton Twp, Hopewell Twp.1106- and 2 more |
217,000 | 8 | 2 | |
|
Aqua NJ Hamilton Square Hamilton Twp |
39,128 | 4 | 2 | |
|
East Windsor Mua East Windsor Twp |
25,000 | 2 | 0 | |
|
Aqua NJ Lawrence Lawrence Twp |
8,655 | 3 | 0 | |
|
Hightstown Water Department Hightstown Boro |
5,400 | 0 | 0 | |
|
Pennington W Dept Pennington Boro |
2,600 | 3 | 2 | |
|
Hopewell Boro W Dept Hopewell Boro |
2,035 | 4 | 2 | |
|
Lawrenceville School Lawrence Twp |
1,200 | 2 | 1 | |
|
Mercer County Correctional Center Hopewell Twp.1106- |
860 | 5 | 1 | |
|
Washington Crossing Park Estates Hopewell Twp.1106- |
356 | 4 | 3 | |
|
Robbinsville Twp Newtown Village Washington Twp |
300 | 2 | 0 |
Non-community systems (88: schools, campgrounds, workplaces, restaurants)
These systems serve places people visit rather than homes.
| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Pennington Shop-Rite Hopewell Twp.1106- |
3,663 | 1 | 0 | |
|
Bent Iron Brewery Hamilton Twp |
1,201 | 1 | 1 | |
|
Terhune Orchards Lawrence Twp |
1,025 | 1 | 0 | |
|
Corner Stone Court Hopewell Twp.1106- |
940 | 1 | 0 | |
|
Timberlane Middle School Hopewell Twp.1106- |
901 | 7 | 0 | |
|
Washington Cross SP Green Grove Pic Area Hopewell Twp.1106- |
720 | 2 | 0 | |
|
Washington Crossing SP Knox Grove Hopewell Twp.1106- |
720 | 1 | 1 | |
|
Washington Crossing SP Visitors Center Hopewell Twp.1106- |
720 | 1 | 1 | |
|
Washington Crossing Sp-Interpretive Ctr Hopewell Twp.1106- |
720 | 1 | 1 | |
|
Washington Crossing State PK Day Use Trl Hopewell Twp.1106- |
720 | 2 | 1 | |
|
Washington Crossing State PK Stone Barn Hopewell Twp.1106- |
720 | 2 | 1 | |
|
The Pennington School Pennington Boro |
565 | 1 | 0 | |
|
Bear Tavern School Hopewell Twp.1106- |
555 | 5 | 1 | |
|
Working Dog Winery Washington Twp |
554 | 0 | 0 | |
|
Hopewell Valley Golf Clu Hopewell Twp.1106- |
548 | 1 | 1 | |
|
Hamilton YMCA at Sawmill Road Hamilton Twp |
498 | 0 | 0 | |
|
Stacys Cream King Pennington Boro |
400 | 3 | 2 | |
|
Wildflowers Hopewell Twp.1106- |
362 | 1 | 1 | |
|
Princeton Community Church Hopewell Twp.1106- |
305 | 1 | 0 | |
|
Unitarian Universalist C Hopewell Twp.1106- |
271 | 0 | 0 | |
|
Tree Farm Village Hopewell Twp.1106- |
230 | 1 | 0 | |
|
Pennington Cleaners Hopewell Twp.1106- |
215 | 1 | 1 | |
|
Golden Nugget Antique Flea Mkt Hopewell Twp.1106- |
205 | 0 | 0 | |
|
Little League of Hopewell Twp Hopewell Twp.1106- |
200 | 2 | 0 | |
|
Princeton RD Professiona East Windsor Twp |
165 | 0 | 0 | |
|
Professor's Hard Cider Washington Twp |
162 | 1 | 1 | |
|
Goddard School West Windsor West Windsor Twp |
155 | 0 | 0 | |
|
The Watershed Institute Hopewell Twp.1106- |
152 | 3 | 0 | |
|
Kooltronic INC Hopewell Twp.1106- |
140 | 1 | 1 | |
|
Titusville Marketplace Hopewell Twp.1106- |
135 | 0 | 0 | |
|
Pennington Montessori School Hopewell Twp.1106- |
133 | 1 | 0 | |
|
Offices at Pennington Point Hopewell Twp.1106- |
125 | 0 | 0 | |
|
Saint Peter Lutheran Church Hopewell Twp.1106- |
125 | 1 | 1 | |
|
Its Nutts Hopewell Twp.1106- |
120 | 0 | 0 | |
|
Titusville Academy Princeton Hopewell Twp.1106- |
116 | 0 | 0 | |
|
Patriots Crossing Restaurant Hopewell Twp.1106- |
112 | 0 | 0 | |
|
Princeton Child Developmnt Ins Lawrence Twp |
110 | 1 | 0 | |
|
Hillbilly Hall, Inc. Hopewell Twp.1106- |
104 | 2 | 1 | |
|
Marcos Pizza Hopewell Twp.1106- |
104 | 2 | 1 | |
|
Mercer Professional Center @ Penn Hopewell Twp.1106- |
100 | 0 | 0 | |
|
Revere Restaurant Ewing Twp |
100 | 0 | 0 | |
|
ST George R C Church Hopewell Twp.1106- |
100 | 1 | 0 | |
|
The Village Learning Center Hopewell Twp.1106- |
100 | 1 | 0 | |
|
Titusville Presbyterian Church Hopewell Twp.1106- |
100 | 0 | 0 | |
|
Hopewell Munic Services Hopewell Twp.1106- |
95 | 2 | 1 | |
|
Word Christian Fellowship Int Hopewell Twp.1106- |
91 | 0 | 0 | |
|
Princeton Windsor Office East Windsor Twp |
85 | 1 | 1 | |
|
Princeton Technology Ctr Hopewell Twp.1106- |
80 | 1 | 1 | |
|
Pennington Point West Hopewell Twp.1106- |
76 | 1 | 0 | |
|
Hopewell Tennis and Swim Hopewell Twp.1106- |
75 | 1 | 1 | |
|
Practice Square Offices East Windsor Twp |
72 | 1 | 0 | |
|
Hopewell Valley Vineyards LLC Pennington Boro |
71 | 1 | 0 | |
|
Camelot Nursery School Hopewell Twp.1106- |
69 | 0 | 0 | |
|
84 Hopewell LLC Hopewell Twp.1106- |
66 | 1 | 0 | |
|
Hopwell Valley Medical Center Hopewell Twp.1106- |
65 | 2 | 1 | |
|
Music & Movement Center Hopewell Twp.1106- |
65 | 0 | 0 | |
|
Zydus Pharmaceuticals Hopewell Twp.1106- |
65 | 3 | 0 | |
|
Eden Autism Clayton Center West Windsor Twp |
60 | 8 | 2 | |
|
2nd Pentecostal Church East Windsor Twp |
55 | 0 | 0 | |
|
Jewish Community Center East Windsor Twp |
55 | 0 | 0 | |
|
Lukoil Station #57703 Hopewell Twp.1106- |
55 | 2 | 2 | |
|
NJ Credit Union League East Windsor Twp |
55 | 0 | 0 | |
|
Kyle Family Farm East Windsor Twp |
54 | 1 | 1 | |
|
Rosedale Park Pump House 1 Hopewell Twp.1106- |
52 | 2 | 1 | |
|
International Process Plants West Windsor Twp |
51 | 2 | 0 | |
|
Etra Lake Park East Windsor Twp |
50 | 1 | 1 | |
|
East Windsor Deli East Windsor Twp |
45 | 0 | 0 | |
|
Hopewell Township Municipal GA Hopewell Twp.1106- |
45 | 1 | 1 | |
|
Pennington Family Chiropractic PC Hopewell Twp.1106- |
44 | 2 | 1 | |
|
Pennington Leasing LLC Pennington Boro |
44 | 1 | 1 | |
|
Alliance Homes East Windsor Twp |
40 | 0 | 0 | |
|
Apple Montessori School Lawrence Twp |
35 | 3 | 1 | |
|
Great Jones Books INC Hopewell Twp.1106- |
35 | 1 | 0 | |
|
Ibew #827 East Windsor Twp |
35 | 0 | 0 | |
|
Pennington Citgo #12261011 Hopewell Twp.1106- |
35 | 0 | 0 | |
|
Union Fire Company & Rescue Squad Hopewell Twp.1106- |
35 | 0 | 0 | |
|
Mercer County Parks Commission Wildlife Hopewell Twp.1106- |
34 | 1 | 1 | |
|
Pennington BP Gas Station #94706 Hopewell Twp.1106- |
33 | 0 | 0 | |
|
Linluks LLC Hopewell Twp.1106- |
32 | 0 | 0 | |
|
Wilson & Apple Funeral Home Hopewell Twp.1106- |
32 | 0 | 0 | |
|
Pennington Office Park-A Hopewell Twp.1106- |
31 | 1 | 1 | |
|
H&h Appliance Center East Windsor Twp |
30 | 0 | 0 | |
|
Bcj&r Hopewell Twp.1106- |
29 | 1 | 1 | |
|
American Legion Post 148 East Windsor Twp |
26 | 1 | 1 | |
|
Shiva 1722 LLC Hopewell Twp.1106- |
26 | 2 | 1 | |
|
The Watershed Institute Hopewell Twp.1106- |
26 | 2 | 1 | |
|
Greater Princeton Investments LLC Hopewell Twp.1106- |
25 | 1 | 0 | |
|
Pennington Office Park-B Hopewell Twp.1106- |
25 | 1 | 0 |
Inactive systems (652, no longer operating or reporting)
Kept for the record and excluded from the county totals above. Browse inactive systems.
About this data
Totals cover active systems. Systems serving more than one county are counted in each county. EPA counts the rules a system was in violation of, not the individual violations; one rule can carry several.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The New Jersey records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.