EPA public water systems for an address, place, point, or state+county. Returns active SDWIS systems with type, population served, and ECHO violation links. National, no key; explicit state+county remains supported. Zero systems can be the real EPA answer. Charge-free when the lookup fails.
| Network | Scheme | Amount | Pay To |
|---|---|---|---|
| Base | exact | $0.05 USDC | 0xf121...431b |