
What does this shelf cover?
Everything between the meter and the ground under the house: cold, water from the river, the limestone below, the septic tank on rural lots, and the permits that govern repairs. Each page starts from one sourced figure. The table gathers them in one place.
| Page | Headline number | Where it comes from |
|---|---|---|
| Freeze nights | 78.4 nights a year at or below 32°F | NOAA 1991–2020 normals, Clarksville WWTP |
| Crawlspace pipes | 27.8°F average January low | NOAA 1991–2020 normals, Clarksville WWTP |
| Leaving the house empty | 55°F minimum thermostat when away | American Red Cross |
| Cumberland River high water | 62.58 ft record crest, May 4, 2010 | NWS gauge CKVT1 |
| Sinkholes and karst | up to 70 ft of Ste. Genevieve limestone | USGS state geologic map |
| Septic in Montgomery County | inspect at least every 3 years | EPA SepticSmart |
| Plumbing permits and licenses | $25,000 per project before a contractor license is needed | Tennessee Board for Licensing Contractors |
Where do Clarksville pipes freeze?
In the cold, unheated places: crawlspaces, garages, outside walls and the spot where the service line enters through the foundation, as the American Red Cross lists them (Red Cross, archived copy). Sixteen nights a year reach 20°F or lower at the treatment-plant station, most of them in January (NOAA NCEI). The month-by-month count and the freeze dates are on freeze nights; the space under the floor gets its own page, crawlspace pipes. If you travel or move in winter, read leaving the house empty first.
Never thaw a pipe with a flame. A hair dryer, a heating pad or hot towels will do it, and a burst pipe means shutting the main water off first.
The Texas Department of Insurance clip below runs through a one-minute winter checklist, including alarms and space-heater cords.
Which pipes are yours to fix?
Everything after the meter. CGW leaves the service line between its meter and the house, and all plumbing indoors, to the property owner (CGW FAQ). Water lost on that stretch is billed; leaks on the meter shows how to catch it.
What else sits under a Clarksville house?
Water and rock. The Cumberland's flood stage at Clarksville is 46 feet, and February holds half of the gauge's top 12 crests; see Cumberland River high water. The county sits on limestone of the Highland Rim, where sinkholes form; see sinkholes and karst. Homes off the sewer system rely on a tank and drainfield permitted by the state; see septic in Montgomery County.
Who can do plumbing work here?
It depends on where you live. City residents cannot take out a plumbing permit themselves, so a licensed contractor must; out in the unincorporated county a homeowner can, by the county's own page. Ask the right office before the job starts. The rules and fees are on plumbing permits and licenses.
Behind these numbers
The figures in the table come from the pages they head, each checked against its source on 6 Nov 2026: NOAA normals for cold, the NWS gauge for the river, the USGS for rock, EPA for septic care and state and local codes offices for permits. A shelf summary drops the caveats, so follow each link for the dates, ranges and gaps behind a number.
Sources
- NOAA NCEI — U.S. Climate Normals 1991–2020, station USC00401790 · first freeze date, freezing and hard-cold nights · checked 6 Nov 2026
- American Red Cross — Preventing & Thawing Frozen Pipes · where pipes freeze, 55°F when away, safe thawing · archived copy of 6 Nov 2026, checked 6 Nov 2026
- NOAA NWS National Water Prediction Service — CKVT1 · flood stage and record crest · checked 6 Nov 2026
- Clarksville Gas & Water — Water Pressure FAQ · owner's stretch of pipe · checked 6 Nov 2026
- USGS — State Geologic Map Compilation, unit TNMsg;3 · Ste. Genevieve limestone, up to 70 ft · checked 6 Nov 2026
- EPA — How to Care for Your Septic System · inspection every three years · checked 6 Nov 2026
- Tennessee Board for Licensing Contractors — Contractor license · $25,000 threshold · archived copy of 14 Apr 2026, checked 6 Nov 2026
- Texas Department of Insurance — How to prepare your home for a winter storm (video) · winter checklist in the clip · checked 6 Nov 2026