Keystone, SD Water Safety: 83/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-03
Compared to statewide averages in SD, Keystone scores well — health violations are below the norm and systems generally operate within federal standards.
How Keystone Compares
Data: EPA SDWIS Last verified: 2026-06-03
What You Should Know About Keystone Water
- Average lead level: 0.004 mg/L.
- Homes built before 1986: 44% — older plumbing may contain lead solder.
- Estimated remediation: $2,200 per household.
- CDC health risk index: 12.98 — above typical levels.
Who Supplies Your Water in Keystone
At present, 2 utilities serve the bulk of Keystone, SD's residential water connections out of 2 systems active in the area, spread across independent providers with separate infrastructure and compliance obligations.
Overview
We track water quality and home safety data for 1 ZIP code in Keystone, South Dakota, covering 2 community water systems serving approximately 996 people.
No EPA violations recorded across any ZIP codes in Keystone — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Keystone: B (83/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Keystone water systems draw from: Groundwater.
Lead & Copper
- Average lead level (90th percentile): 0.0040 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 57751 | B | Southern Black Hills Water | 492 |
All ZIP Codes in Keystone
- 57751 [B]
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
Health Outcomes in Keystone
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Housing & Infrastructure in Keystone
With 44% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Housing age is a practical proxy for plumbing risk because federal standards changed in 1986, when lead solder was banned from new residential construction, and again earlier — before 1970, lead pipes were themselves commonly installed. Keystone's median build year of 1999 sits in the range where both pre- and post-1986 homes are well represented. The bar chart above reflects that mixed picture: the distribution captures pockets of older housing alongside more recent development, and those pockets carry real lead risk potential at the individual property level.
Most homes in Keystone were built after 1986, reducing the risk of lead contamination from plumbing. Older homes should still be tested.
Source: U.S. Census Bureau ACS B25034.
Cost Context: What Remediation Means for Keystone Homeowners
Given current Keystone valuations, the remediation-to-property-value ratio is low — most homeowners are looking at a proportionally modest share that fits within routine financial planning.
Remediation costs in Keystone are relatively low compared to home values. The $1,200–$3,400 estimated range is a small fraction of median property value. Home values are 122% above the South Dakota average.
Lead Exposure Risk for Children in Keystone
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Routinely in Keystone, where 44% of housing predates the solder ban and aggregate utility readings hover near the federal threshold, a faucet-level draw functions as a standard household step for families with small kids.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Flood & Climate Risk in Keystone
Flood risk in Keystone occupies the middle ground: 4 NFIP claims and 100% of local ZIP codes within FEMA flood zones. At that level, the risk pathways connecting flooding to water quality — treatment system stress, well infiltration, distribution backflow — become relevant considerations during significant flood events, even if day-to-day water quality is unaffected by flood history.
Keystone has a moderate flood history with 4 FEMA claims averaging $587 per payout. 100% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$2,200</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
Deep Dive Reports
Detailed analysis for Keystone, SD