Connecticut Well Data · Well logs
Connecticut well logs
Every time a well is drilled in Connecticut, the driller files a completion report — the well log — with the USGS National Water Information System groundwater site inventory. We hold 6,179 of them and rebuild this index weekly, so you can find one by address instead of by record number.
✓ Verified against USGS NWIS · 2026-08-28
Heads up: we re-read USGS NWIS weekly and hold every record it publishes, but the newest filed log in the source itself is from 2011. A well drilled since then very likely has no log here yet — that's the state's publishing cadence, not a gap in our copy. Everything below describes the 6,179 records that do exist.
Well logs are filed by location, not by house number. Enter any Connecticut address and we'll pull the recorded wells around it — These are the wells the U.S. Geological Survey has inventoried in Connecticut — a large sample of the state's wells, not every well drilled — so results show the wells around a location rather than a single wellhead.
Free address lookup Full property report — $29What's in a Connecticut well log
Not every filed report carries every field — older logs are thinner, and what the state captured changed over the decades. This is the actual coverage across all 6,179 records, so you know what to expect before you look anything up.
| Field | What it tells you | Records with it | Coverage |
|---|---|---|---|
| Total depth | How deep the hole was drilled, in feet. | 6,179 (100%) | |
| Mapped location | Coordinates, so the log can be found by address instead of by record number. | 6,179 (100%) | |
| Original log document | A direct link to the USGS NWIS copy of the filed log itself. | 6,179 (100%) | |
| Date completed | When the well was finished and the log filed. | 5,353 (87%) |
When Connecticut's wells were drilled
Dated logs by decade of completion (5,353 of 6,179 records carry a usable completion date). The shape of this chart is mostly the history of the filing requirement, not of drilling — thin early decades mean the logs weren't kept, not that nobody drilled.
| Decade | Logs filed | |
|---|---|---|
| 1880s | 1 | |
| 1890s | 1 | |
| 1900s | 19 | |
| 1910s | 77 | |
| 1920s | 133 | |
| 1930s | 216 | |
| 1940s | 291 | |
| 1950s | 1,224 | |
| 1960s | 1,743 | |
| 1970s | 650 | |
| 1980s | 624 | |
| 1990s | 263 | |
| 2000s | 108 | |
| 2010s | 3 |
Three ways to find a well log here
- By address — the free lookup maps an address to the wells recorded around it. This is what most people want: "how deep is the well on the place I'm buying."
- By county — each county page carries the median depth, water level and yield computed from every log filed there, plus the drillers working it.
Well logs by county
See all 9 Connecticut counties →
Where these records come from
All of it is public record from the groundwater wells the U.S. Geological Survey has inventoried in Connecticut (waterdata.usgs.gov/ct/nwis/gw). We don't hold anything the state doesn't publish. More on that database and what a filed record carries: USGS NWIS well records. What we add is that the records are indexed by location, the statistics are computed the same way in every county, and the whole thing is refreshed weekly. Our filters and the exact computation are on the methodology page (statistics use USGS NWIS groundwater inventory, water-supply wells only (monitoring wells, test holes and injection wells excluded), and only wells carrying a measured depth).
Common questions
Yes. Connecticut drillers are required to file a completion report for each well, and those reports are kept by the USGS National Water Information System groundwater site inventory. Anyone can look them up. This site is an independent index of that public record — we re-read the source and recompute every page weekly.
Well logs are filed by location, not by street address, so you search the map rather than a house number. Enter the address on our free lookup and you'll see the recorded wells around that spot — These are the wells the U.S. Geological Survey has inventoried in Connecticut — a large sample of the state's wells, not every well drilled — so results show the wells around a location rather than a single wellhead. Each one shows its depth, static water level, tested yield, and a link to the original filed log.
The oldest dated log in our copy was completed in 1888; the newest is from 2011. Coverage thins out the further back you go — older wells were often never filed, and filing requirements tightened over time.
Most likely it was never filed. Wells drilled before the state's reporting requirement — and hand-dug or unpermitted wells — have no log at all. It also happens that a log exists but its recorded location is off, in which case it will show up under a neighboring property. Neither is something we can fix from the source data, and we'd rather say so than invent a record.
The useful parts for a buyer or a homeowner: how deep the well is, how high the water stands in it, how many gallons per minute it produced when tested, what the driller hit on the way down, and who drilled it. Together those say whether the well is likely to keep producing and what a replacement would cost.
The property report pulls every recorded well near an address — depths, water levels, yields, drillers , and links to each original filed log — as one printable summary for due diligence.
Property report — $29Driller, agent, or inspector pulling these regularly? Unlimited & white-label plans →