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Tap Water Map
BY TAMAS KALMAN · FROM THE IDEA TAP WATER QUALITY DIRECTORY (VERDICT: BUILD)
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THE STORY
A US tap-water directory built entirely on the EPA's own SDWIS data — the calm middle between fear-blogs and government PDFs. Every city page is computed in code from EPA records (zero per-page AI prose — that's how a programmatic site survives Google's YMYL/scaled-content bar), match-gated to real active community water systems, and reported only against federal limits.
Shipped ~19,400 city pages across all 50 states + DC (~38k incl. a Spanish version), summarizing 1.5M EPA violation records. Static Astro → Cloudflare Pages, R2-cached, weekly auto-rebuild, ~$0 running cost. Just launched, so the SEO bet is young: this is a 12–18-month compounding play, and the real prize is the reusable programmatic-directory engine for the next idea.
LESSONS LEARNED
Don't trust the obvious data join. The "natural" key — EPA's city_served field — was full of defunct restaurants and bars and would've spawned thousands of junk pages; I had to reverse the whole pipeline to start from active community water systems instead. For a YMYL/health topic, compute every fact from the source in code and never let an LLM write the page — that's the line between ranking and getting buried. And go in clear-eyed: programmatic SEO is a slow compounding bet, not a quick flip.
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