Is Denning (T), NY Tap Water Safe to Drink?
Graded B+ — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
83.3/100
waterverge.com Denning (T), NY — Water Quality Report
Denning (T)'s drinking water received a grade of B+ (83.3 out of 100), indicating good water quality. The city's 1 water system serves approximately 688 residents using groundwater.
Lead levels were measured at 1.1 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 47 violations on record, including 1 health-based violation. 6 remain unresolved.
What to know about Denning (T)'s water
Denning (T) ranks #490 out of 855 cities in New York for water quality, placing it below average in the state.
Denning (T) relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
As a small community water system, Denning (T) may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Denning (T), NY water safe to drink?
Denning (T)'s drinking water has significant quality concerns based on EPA testing data. With a grade of B+ (83.3/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 688 residents using groundwater (wells).
Recent water quality updates for Denning (T)
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Denning (T)'s water quality assessment. Grade: B+ (83.3/100).
Contaminants: Lead and Copper Rule.
Contaminants: Lead and Copper 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.
Contaminants: Lead and Copper Rule.
Key contaminant findings
Based on the most recent EPA sampling data for Denning (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
Denning (T)'s water system has 47 total violations on record, including 1 health-based violation. 6 remain unresolved. 3 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 Rondout Creek, Pepacton Res Div Outlet Nr Grahamsville, Cannonsville Res Div Channel Nr Grahamsville, Chestnut Creek, Neversink Res Diversion Channel.
Where does Denning (T)'s water come from?
Denning (T)'s drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 688 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Rondout Creek (river), Pepacton Res Div Outlet Nr Grahamsville (river), Cannonsville Res Div Channel Nr Grahamsville (river), Chestnut Creek (river), Neversink Res Diversion Channel (river).
What Denning (T) residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Denning (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.
Denning (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 Denning (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. | 1.1 | 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. | 1.42 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Denning (T) compares by contaminant
Explore where Denning (T) ranks among all New York cities for specific contaminants.
Water source & infrastructure
Where Denning (T)'s water comes from
Denning (T)'s drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by private ownership and serves approximately 688 people through 1 water system.
Water bodies near Denning (T)
Denning (T) is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Denning (T)
| System Name | PWSID | Population | Source |
|---|---|---|---|
| FROST VALLEY YMCA | NY5507411 | 688 | GW |
How Denning (T) compares
Full New York rankings →Denning (T)'s score of 83.3/100 is above the average of 74/100 among major New York cities. It outscores 7 of 10 nearby cities.
Nearby cities
View New York rankings →Learn more about your water
Guides and resources related to Denning (T)'s water quality findings.
Explore water quality across Ulster
Frequently asked questions
Is Denning (T), NY tap water safe to drink?
Denning (T)'s water quality earned a grade of B+ (83.3/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #490 out of 855 cities tested in New York.
What contaminants are in Denning (T)'s water?
Lead was measured at 1.1 ppb (90th percentile). 47 violations are on record.
How is Denning (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 Denning (T)?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Denning (T)'s water come from?
Denning (T)'s water is sourced from Groundwater. The city has 1 water system serving approximately 688 residents.
What health violations has Denning (T)'s water system had?
Denning (T) has 1 health-based violation on record. The most recent violation was recorded in January 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 6 violations remain unresolved.
Is Denning (T)'s groundwater at risk of contamination?
Denning (T) uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 47 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Denning (T)'s water compare to other cities?
Denning (T) ranks #490 out of 855 cities in New York (better than 43% of state cities) and #6511 out of 15744 cities nationally (59th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Denning (T)'s small water system affect quality?
Denning (T)'s system serves approximately 688 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 47 violations on record.