01The verdict: is Mount Holly water safe?
Based on EPA testing data, Mount Holly's tap water is generally safe to drink. The water system earned a grade of A+ (95.2/100), meeting federal drinking water standards across key contaminant categories. The city's 1 water system serves approximately 867 residents using groundwater (wells).
Nothing over a legal limit
Every contaminant measured in Mount Holly's water is within its EPA limit, and no violations are unresolved.
See the testing ↓Lead is well under the limit
90th-percentile lead is 1.0 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓A flood-prone service area
8 federal disaster declarations on record. After severe weather, watch for boil-water advisories.
See the risk factors ↓Mount Holly's drinking water received a grade of A+ (95.2 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 867 residents using groundwater.
Lead levels were measured at 1.0 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 9 violations on record, including 4 health-based violations. All violations have been resolved.
Mount Holly ranks #22 out of 345 cities in Arkansas for water quality, placing it one of the best in the state. Mount Holly 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, Mount Holly may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Mount Holly's water
Every contaminant flagged in Mount Holly, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
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. | 1.0 | 15 | ppb | Inorganic | Safe |
Cities ranked by 90th-percentile lead PF PFAS in Arkansas
Cities ranked by compounds detected Cu Copper in Arkansas
Cities ranked by 90th-percentile copper
03Mount Holly's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 9 violations on record, including 4 health-based violations. All violations have been resolved.
All ten of the last ten years were clean — no EPA violations recorded for Mount Holly.
▼ Down 3 ppb since 1993. Latest reading: 1 ppb (2006) — 7% of the action level. Sampled at higher-risk homes (90th percentile).
04Where Mount Holly's water comes from
Mount Holly's drinking water is drawn from underground aquifers through wells.
Groundwater
Underground aquifers reached by wells — naturally filtered, but can carry minerals like arsenic and nitrate.
Local treatment
Groundwater generally needs less treatment — typically disinfection and, where needed, mineral removal.
1 system
1 water system, operated under local government ownership.
867 people
Residents served across Mount Holly's service area.
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 local government ownership and serves approximately 867 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| MARYSVILLE WATER ASSOCIATION | AR0000001 | 867 | Groundwater |
05Pressure on Mount Holly's watershed
Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.
Industrial discharge
1 facility within 10 miles reported 0 lb released to surface water in the latest EPA Toxics Release Inventory. Proximity doesn't equal tap contamination — treatment and hydrology decide — but it's pressure on the watershed.
Flood & storm history
8 federal disaster declarations on record for Union County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
Drought
Union County is in D2 (severe drought) per the U.S. Drought Monitor (week of Jul 2026). Drought can raise disinfection-byproduct levels and taste/odor issues as utilities draw from lower reservoirs.
06How Mount Holly compares
Scores for nearby Arkansas cities on one line, with the average marked.
dashed line = Arkansas average (75/100)
Mount Holly scores 95.2/100 — above the Arkansas average of 75/100. It outscores 9 of 10 nearby cities. Full Arkansas rankings →
69.3 / 100DFayetteville, AR
46.4 / 100BSpringdale, AR
79.1 / 100DFort Smith, AR
45.5 / 100BHot Springs, AR
81.2 / 100BRogers, AR
71.9 / 100
Compare all cities in the county — grades, violations, and contaminant data side by side.→
07What to do at home
Steps matched to what testing actually found in Mount Holly's water — not generic advice.
A basic carbon filter still helps
Mount Holly's water meets federal standards, but a simple carbon filter improves taste and adds a margin of safety against short-term issues.
Compare tested filters →Read your utility's annual report
Every utility must publish a yearly Consumer Confidence Report with its own testing results. It pairs well with the independent data on this page.
How to read a CCR →Watch for Mount Holly alerts
This area has a history of flood declarations — after severe weather, watch for boil-water advisories from the utility, and check the live alerts on this page.
All water alerts →Frequently asked questions
Is Mount Holly, AR tap water safe to drink?
Mount Holly's water quality earned a grade of A+ (95.2/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #22 out of 345 cities tested in Arkansas.
What contaminants are in Mount Holly's water?
Lead was measured at 1.0 ppb (90th percentile). 9 violations are on record.
How is Mount Holly'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 Mount Holly?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Mount Holly's water come from?
Mount Holly's water is sourced from Groundwater. The city has 1 water system serving approximately 867 residents.
What health violations has Mount Holly's water system had?
Mount Holly has 4 health-based violations on record. The most recent violation was recorded in April 2015. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. All health violations have been resolved.
Is Mount Holly's groundwater at risk of contamination?
Mount Holly 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 9 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 Mount Holly's water compare to other cities?
Mount Holly ranks #22 out of 345 cities in Arkansas (better than 94% of state cities) and #341 out of 15382 cities nationally (98th percentile). The grade of A+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Mount Holly's small water system affect quality?
Mount Holly's system serves approximately 867 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 9 violations on record.