Water quality by ZIP code

SDWIS (Safe Drinking Water Information System)

EPA's federal database of every community water system, its violations, lead-and-copper sampling, and treatment data.

LCRR (Lead and Copper Rule Revisions)

EPA's 2024 update tightening lead-pipe inventories, sampling procedures, and trigger thresholds for action by water systems.

Tier 1 violation (acute health-based)

Most-serious water-quality violation requiring 24-hour public notice — coliform/E. coli, nitrate exceedance, chlorine dioxide exceedance.

Septic system (on-site wastewater)

Self-contained wastewater treatment for properties without public sewer — typically tank + leach field + soil percolation.

Perc test (percolation test)

Soil-permeability test required by health department before installing septic system or building on undeveloped land.

Flood zones explained — what AE, X, and VE actually mean

Plain-English guide to FEMA flood-zone codes (A, AE, AH, V, VE, X, X-shaded). What the 1% and 0.2% annual-chance zones mean for your property and your insurance.

EPA Radon Zones — what 1, 2, and 3 mean and when you should test

EPA classifies every US county into Zone 1 (high), Zone 2 (moderate), or Zone 3 (low) for radon. Plain-English guide to the classifications and at-home testing.

Lead and Copper Rule 2024 — the federal lead-pipe inventory mandate

The 2024 Lead and Copper Rule Revisions (LCRR) require every US community water system to inventory and report lead service lines. Plain-English guide.

AQI explained — what 50, 100, 150 actually mean for your lungs

Plain-English guide to the EPA Air Quality Index (AQI) and the 6 categories from Good to Hazardous. When to take precautions and which pollutants matter.

EPA SDWIS — how to read drinking-water violations and what they actually mean

Plain-English guide to EPA SDWIS drinking-water violations: health-based vs. monitoring vs. reporting violations, MCLs, and what triggers a public notice.

AirNow + wildfire smoke — when AQI is a real-time tool

How EPA AirNow handles real-time wildfire smoke, what the colors mean during fire season, and where AirNow leaves gaps you should know about.

Radon and real estate — what disclosure laws and home tests actually require

What home sellers must disclose about radon by state, when home tests are required, and how to interpret radon-mitigation systems if a home you're buying has one.

EPA SDWIS — reading drinking-water violations without panicking

EPA's drinking-water database flags violations across every public water system. Here's how to read what's in your ZIP — and what 'violation' actually means.

Buying a house — the 12-dimension data checklist before you sign

Twelve federated public-records dimensions every US homebuyer should check before closing. Synthesized from EPA, FEMA, FBI, NCES, county assessors + recorders.

Private well water — what to test when EPA SDWIS doesn't cover you

EPA SDWIS only covers public water systems. Private wells (~13% of US homes) are the homeowner's responsibility. Here's what to test, how often, and what each test costs.

PFAS in drinking water — what 2024's new MCLs actually mean

EPA finalized first-ever drinking-water MCLs for PFAS in April 2024. Here's what's covered, the 5-year compliance timeline, and how to read your utility's testing.

Lead in paint vs. lead in pipes — same metal, different exposure

Lead service lines (LCRR) and lead-based paint (Title X) are governed by separate regulatory regimes. Here's how each one matters when buying an older home.

EPA Superfund + Brownfields — what 'contaminated site nearby' actually means

EPA's National Priorities List (Superfund) flags the most contaminated sites in the US. Brownfields tracks lower-tier abandoned-industrial sites. Here's how to read both.

Data staleness — when to re-check zipradar before making a decision

Federal data refreshes on different cadences. Here's when zipradar's snapshot is fresh enough for your decision and when you need to verify with the primary source.

Septic systems — what they fail on, what tests cost, when they're a deal-breaker

About 21% of US homes use a septic system. They fail in patterns. Here's the inspection cost, common failures, and when a failed septic is reason to walk from a deal.

Groundwater vs municipal water — which does your address have, and how to tell

About 13% of US households are on private wells. Here's how to tell which water source serves your address — and what each means for testing, cost, and quality.

Drought, water rights, and private wells — when your tap runs dry

How drought levels affect well users in the West, water-rights doctrine (riparian vs. prior-appropriation), and what to verify before buying a property on private well in a drought-prone state.