How we verify listings

How a listing gets here

Something outside this website has to confirm that hot water comes out of the ground at that spot before it earns a page. Every listing is graded against NOAA’s Thermal Springs List for the United States — 1,661 surveyed natural vents with measured temperatures — and against hot spring, thermal bath and public bath features in OpenStreetMap. Neither is complete on its own. NOAA’s survey is from 1980, covers 23 states and deliberately excludes wells; OpenStreetMap covers the wells and the bathhouses but misses springs nobody has mapped. Together they cover most of each other’s gaps.

The directory was first assembled from map data, and map data matches on names. That filled it with hot tub showrooms, holiday lets, a casino, a zipline course and a Clydesdale breeding farm — every one of them with “hot springs” in its name. Several hundred listings have been removed since, and the same checks run again every month so they cannot come back.

Every fact shows its source

Temperature, clothing policy, road access, vehicle requirements and camping each carry a label saying how that one fact was established:

• Verified: Stated on the operator's official website.
• Survey-measured: Measured at the vent by a federal thermal-springs survey.
• Visitor-confirmed: Confirmed by two or more independent visitor reviews.
• Listed data: From the venue's published business listing.
• Unverified: No source confirms this — call ahead before you rely on it.

“Unverified” means nobody has confirmed it. It does not mean no, and it does not mean yes. Where nothing confirms a fact, the listing says so rather than guessing.

Which pages are kept out of search

A listing where no fact has a source is thin by construction: every claim on it would be the directory’s own classification, hedged as unverified. Those listings stay on the site and stay linked, but they are marked noindex, left out of the sitemap and carry no ads. Today that is 86 of 277 listings; the other 191 have at least one sourced fact. The moment a real source is added to one, it is indexed again on its own.

Town pages listing a single spring are kept out of search the same way, since they repeat the listing beneath them. Permanently closed springs keep their page as a record, with every booking link, affiliate link and ad removed.

How road access is measured

Every coordinate is snapped onto the nearest edge of the OSRM driving network, which is built on OpenStreetMap data, to find how far the nearest drivable road is. The distance reported is straight-line from the spring to that point, so it is a lower bound on the walk in, not a trail distance. A spring more than 0.25 miles from a drivable road counts as hike-in; 34 springs are past that line. The full dataset and method are published in the road access report, free to reuse under CC BY.

Where the photos come from

A photo appears only if its licence allows use on a site that carries ads and affiliate links, and it is credited on the page with its author and licence: public-domain federal photos, Creative Commons photos that allow commercial use, photos operators have given permission to use, and photos visitors submit with a condition report, which are reviewed before they appear. They are hosted on this site. Photos from Google (Maps place photos and Street View) are not shown, and the code drops any such address before a page is built. Where there is no usable photo, the listing has no photo rather than a borrowed one. Today 57 of 277 listings have one.

What this method cannot tell you

• A surveyed temperature is the temperature at the vent, not the pool. 187 of the 256 listings with a temperature take it from the NOAA survey, and they say so on the page. Where a spring runs into a creek, the water you can actually sit in is cooler — sometimes much cooler. Always test before getting in.
• Distance to a road is straight-line, not trail miles. The walk in is always longer, and sometimes far longer. The nearest routable road is not always the road people use, and OpenStreetMap coverage of forest tracks is uneven.
• Clothing policies and vehicle requirements are the fields most often unverified, and they are exactly the two worth ringing ahead about.
• Conditions change and this page does not know when. Roads wash out, seasons close pools, and operators change their rules. Listings are re-checked monthly, which is often enough to catch a closure and not often enough to catch last week’s storm.
• It is not a census. The catalogue of 277 springs is not every hot spring in the United States.

Corrections

If something on a listing is wrong — a closed road, a spring that has dried up, a policy that changed — email alex@usnaturalhotsprings.com with the listing link. I check it and fix the listing; an operator who asks for a page that is not a hot spring, or not on their property, to be taken down gets it removed. What to send and when to expect a reply is on the contact page.

Money and independence

Listings are free, and no one can pay to be listed, ranked higher or described differently. State pages rank springs by what is confirmed: verified geothermal activity first, then how many facts carry a source, then review volume. How the site earns money — ads and affiliate links — is set out on the affiliate disclosure page.