Is Thompson (T), NY Tap Water Safe to Drink?
Graded D — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
45/100
waterverge.com Thompson (T), NY — Water Quality Report
Thompson (T)'s drinking water received a grade of D (45 out of 100), indicating poor water quality. The city's 19 water systems serve approximately 8,662 residents using surface water.
Lead levels were measured at 1.8 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 563 violations on record, including 6 health-based violations. 62 remain unresolved.
What to know about Thompson (T)'s water
Thompson (T) ranks #831 out of 855 cities in New York for water quality, placing it among the lowest-rated in the state.
The city draws from surface water sources, which are more susceptible to seasonal runoff and agricultural contamination, requiring extensive multi-barrier treatment including coagulation, filtration, and disinfection.
The system has seen 107 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Thompson (T), NY water safe to drink?
Thompson (T)'s drinking water has significant quality concerns based on EPA testing data. With a grade of D (45/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 19 water systems serve approximately 8,662 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Thompson (T)
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Thompson (T)'s water quality assessment. Grade: D (45/100).
Contaminants: Public Notice, Revised Total Coliform Rule.
Contaminants: Revised Total Coliform Rule.
Contaminants: Revised Total Coliform Rule.
Federal disaster declaration (FEMA DR-4615). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3572). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Thompson (T)'s water supply.
Well within EPA limits.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Thompson (T)'s water system has 563 total violations on record, including 6 health-based violations. 62 remain unresolved. 107 violations were issued in the last 5 years.
Flood & environmental risk
Sullivan County has experienced 10 federally declared disasters since 1984. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Sheldrake Stream, Neversink River, Gumaer Brook, Basher Kill.
Where does Thompson (T)'s water come from?
Thompson (T)'s drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 19 water systems serving approximately 8,662 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment. Nearby water bodies include Sheldrake Stream (river), Neversink River (river), Gumaer Brook (river), Basher Kill (river).
What Thompson (T) residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Thompson (T)'s water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Thompson (T)'s area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Flood & disaster history
Sullivan County has experienced 10 federally declared disasters since 1984. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Thompson (T)'s water supply, we recommend the following filter types.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 1.8 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 1.40 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Thompson (T) compares by contaminant
Explore where Thompson (T) ranks among all New York cities for specific contaminants.
Water source & infrastructure
Where Thompson (T)'s water comes from
Thompson (T)'s drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Surface water systems require multi-stage treatment including coagulation, sedimentation, filtration, and disinfection to meet EPA Safe Drinking Water Act standards.
These sources can be impacted by seasonal changes, stormwater runoff, upstream agriculture, and industrial discharge.
The system is operated by private ownership and serves approximately 8,662 people through 19 water systems.
Water bodies near Thompson (T)
Thompson (T) is located near 4 notable water bodies. As a surface water system, these water bodies may directly influence the city's drinking water supply.
Water systems serving Thompson (T)
| System Name | PWSID | Population | Source |
|---|---|---|---|
| EMERALD GREEN LAKE LOUISE MARIE WC | NY5203346 | 2,400 | SW |
| ADELAAR WD | NY5230211 | 1,000 | SWP |
| KIAMESHA ARTESIAN SPRING WATER COMPANY | NY5203344 | 879 | GW |
| KINNEBROOK ESTATES MHP | NY5201346 | 680 | GW |
| TCFD - HARRIS | NY5225004 | 600 | GW |
| PARKSIDE ESTATES | NY5230258 | 600 | GW |
| HARRIS WOODS HOA | NY5221008 | 440 | GW |
| WINDSOR HILL ESTATES | NY5230257 | 384 | GW |
| KIAMESHA-ROUTE 42 WD | NY5220223 | 331 | GWP |
| FOREST PARK ESTATES | NY5230201 | 300 | GW |
| CHARM ESTATES | NY5230263 | 280 | GW |
| GREENTREE WATER COMPANY | NY5221394 | 184 | GW |
| MELODY LAKE WD | NY5205653 | 150 | GW |
| CRYSTAL WATER SUPPLY COMPANY | NY5220222 | 146 | GW |
| COLD SPRING RD WD - THOMPSON | NY5220343 | 82 | GW |
| SACKETT LAKE ESTATES | NY5230003 | 80 | GW |
| LUCKY LAKE WD | NY5203356 | 60 | GW |
| BROOKSIDE MOBILE HOME PARK | NY5201341 | 36 | GW |
| DILLON FARM WD | NY5203350 | 30 | GW |
How Thompson (T) compares
Full New York rankings →Thompson (T)'s score of 45/100 is below the average of 74/100 among major New York cities. 10 of 10 nearby cities score higher.
Nearby cities
View New York rankings →About Thompson (T), NY
Wikipedia →Rock Hill is a hamlet in Sullivan County, New York, United States. At the 2020 census the population was 2,369.
Learn more about your water
Guides and resources related to Thompson (T)'s water quality findings.
Explore water quality across Sullivan
Frequently asked questions
Is Thompson (T), NY tap water safe to drink?
Thompson (T)'s water quality earned a grade of D (45/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #831 out of 855 cities tested in New York.
What contaminants are in Thompson (T)'s water?
Lead was measured at 1.8 ppb (90th percentile). 563 violations are on record.
How is Thompson (T)'s water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Thompson (T)?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Thompson (T)'s water come from?
Thompson (T)'s water is sourced from Surface water. The city has 19 water systems serving approximately 8,662 residents.
What health violations has Thompson (T)'s water system had?
Thompson (T) has 6 health-based violations on record. The most recent violation was recorded in November 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 62 violations remain unresolved.
How does Thompson (T)'s water compare to other cities?
Thompson (T) ranks #831 out of 855 cities in New York (better than 3% of state cities) and #14224 out of 15744 cities nationally (10th percentile). The grade of D reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.