Bare steel, and why it is the number to know
14,326 tanks — 30.1% of the register — are recorded as asphalt-coated or bare steel.
The one physical fact these files carry
Most of what a tank register records is administrative. The material is not: it is a physical property of the tank, and it decides how a tank fails. Unprotected steel in wet ground corrodes; corrosion makes holes. That is the whole mechanism, and it is why the federal upgrade rules required protection — cathodic protection, a fibreglass shell, or fibreglass throughout.
| Material recorded | Tanks | Share |
|---|---|---|
| Asphalt Coated or Bare Steel | 14,326 | 30.1% |
| FRP: Fiberglass Reinforced Plastic | 5,776 | 12.2% |
| ST: Cathodically Protected Steel | 5,704 | 12.0% |
| Unknown | 4,846 | 10.2% |
| AST: UL142/Equiv. | 4,399 | 9.3% |
| AST: UL2085/Equiv. (Protected) | 1,434 | 3.0% |
| Not Listed | 1,181 | 2.5% |
| Fiberglass Reinforced Plastic | 669 | 1.4% |
⚠️ What this number is not
Not a leak, and not a breach. Many of these tanks are long closed — the register keeps them. The file records what a tank is made of, not its condition, and a maintained, monitored steel tank is not the same as one forgotten under a car park.
Read with the year the tank went in, which the record also carries, it is the closest a public file gets to telling you whether to look harder.
⚠️ And one field we do not use
The register has a tank_wall_type column — single or
double walled — which would be genuinely useful. It is filled on
1,013 rows out of 51,987. We load it and never put it on a
page: a field filled at 2 % that appears in a table reads as information when
it is a hole.
Where they are
| County | Facilities | Share |
|---|---|---|
| Denver | 2,630 | 13.3% |
| El Paso | 1,871 | 9.5% |
| Adams | 1,578 | 8.0% |
| Jefferson | 1,411 | 7.1% |
| Arapahoe | 1,256 | 6.4% |
| Weld | 1,156 | 5.8% |
| Larimer | 943 | 4.8% |
| Mesa | 708 | 3.6% |
| Boulder | 707 | 3.6% |
| Pueblo | 630 | 3.2% |
| Douglas | 495 | 2.5% |
| Garfield | 372 | 1.9% |
| Eagle | 316 | 1.6% |
| La Plata | 277 | 1.4% |
| Grand | 258 | 1.3% |
| Montrose | 246 | 1.2% |
| Fremont | 228 | 1.2% |
| Routt | 218 | 1.1% |
| Morgan | 214 | 1.1% |
| Montezuma | 206 | 1.0% |
| Pitkin | 198 | 1.0% |
| Chaffee | 187 | 0.9% |
| Delta | 185 | 0.9% |
| Logan | 184 | 0.9% |
| Summit | 178 | 0.9% |
| Rio Grande | 168 | 0.9% |
| Broomfield | 157 | 0.8% |
| Gunnison | 155 | 0.8% |
| Otero | 152 | 0.8% |
| Las Animas | 131 | 0.7% |
County pages break out how many of their facilities carry bare steel. The count for one facility is on its own record, one search away.
An old steel tank on a property you own or are buying?
The register says what a tank is made of and when it went in. It does not say what condition it is in — that takes someone on site.
We take no commission and we recommend no firm. We have no arrangement with any contractor today — we are collecting these requests in order to go and find them. What we do with this.