01The verdict: is Marion water safe?
Marion's drinking water has significant quality concerns based on EPA testing data. With a grade of A- (85.2/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 894 residents using groundwater (wells).
Copper is over its legal limit
Measured at 1.45 mg/L against the EPA Action Level of 1.3 mg/L. The ledger below shows how far over — and which filter removes it.
See the measurement ↓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
10 federal disaster declarations on record. After severe weather, watch for boil-water advisories.
See the risk factors ↓Marion's drinking water received a grade of A- (85.2 out of 100), indicating good water quality. The city's 1 water system serves approximately 894 residents using purchased ground water.
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 0 health-based violations. 4 remain unresolved.
Marion ranks #77 out of 137 cities in South Dakota for water quality, placing it below average in the state. Marion purchases its water from a regional wholesaler, meaning quality depends on both the supplier's treatment and the local distribution system's condition. As a small community water system, Marion may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Marion's water
Every contaminant flagged in Marion, 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.
Over Limit — EPA Action Level: 1.3 mg/L
Exceeds the EPA action level. Copper leaches from household plumbing — flush taps for 30 seconds before drinking, and consider a certified filter.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 |
| 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. | 1.45 | 1.3 | mg/L | Inorganic | Over Limit |
Cities ranked by 90th-percentile lead PF PFAS in South Dakota
Cities ranked by compounds detected Cu Copper in South Dakota
Cities ranked by 90th-percentile copper
03Marion'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 0 health-based violations. 4 remain unresolved.
All ten of the last ten years were clean — no EPA violations recorded for Marion.
▼ Down 2 ppb since 1993. Latest reading: 1 ppb (2023) — 7% of the action level. Sampled at higher-risk homes (90th percentile).
▲ Up 0.02 mg/L since 1993. The latest reading (1.4 mg/L, 1994) is over the action level. Sampled at higher-risk homes (90th percentile).
04Where Marion's water comes from
Marion purchases its water supply from a regional wholesale provider rather than treating raw water directly.
Purchased Groundwater
Water is bought from a regional wholesaler; quality starts at the supplier's intake and treatment.
Wholesale supplier
Primary treatment happens at the wholesaler; the local utility maintains disinfectant residual in its pipes.
1 system
1 water system, operated under local government ownership.
894 people
Residents served across Marion's service area.
Water quality depends on both the wholesaler's treatment standards and the condition of Marion's local distribution pipes and storage facilities. Purchased water systems are common in suburban areas and smaller communities that lack the infrastructure for independent treatment. The system is operated by local government ownership and serves approximately 894 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| MARION | SD4600201 | 894 | Purchased Groundwater |
Water bodies near Marion
These water bodies shape the regional watershed and can indirectly affect groundwater quality.
05Pressure on Marion'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
2 facilities 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
10 federal disaster declarations on record for Turner County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
Drought
Turner 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 Marion compares
Scores for nearby South Dakota cities on one line, with the average marked.
dashed line = South Dakota average (66/100)
Marion scores 85.2/100 — above the South Dakota average of 66/100. It outscores 6 of 10 nearby cities. Full South Dakota rankings →
58.2 / 100FRapid City, SD
38.7 / 100FAberdeen, SD
41.8 / 100AWatertown, SD
91 / 100FPine Ridge, SD
43.2 / 100DBrookings, SD
46.2 / 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 Marion's water — not generic advice.
Filter drinking & cooking water
NSF-certified water filter. Copper exceeds the EPA action level of 1.3 mg/L
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 Marion 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 Marion, SD tap water safe to drink?
Marion's water quality earned a grade of A- (85.2/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #77 out of 137 cities tested in South Dakota.
What contaminants are in Marion's water?
Lead was measured at 1.0 ppb (90th percentile). 9 violations are on record.
How is Marion'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 Marion?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Marion's water come from?
Marion's water is sourced from Purchased ground water. The city has 1 water system serving approximately 894 residents.
Is Marion's groundwater at risk of contamination?
Marion 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 Marion's water compare to other cities?
Marion ranks #77 out of 137 cities in South Dakota (better than 44% of state cities) and #5436 out of 15382 cities nationally (65th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Marion's small water system affect quality?
Marion's system serves approximately 894 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.