St. Lawrence County, New York · Canton
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Pipes freeze in St. Lawrence County on about 80 nights a year, mostly November to April. Older homes, 47% of the stock here, are most at risk.
Heavy rain days of an inch or more come about 4.5 times a year here, most often in July. A sump pump that hasn't run since last season is a common weak point.
Backups often follow heavy rain, which St. Lawrence County gets about 4.5 days a year, when storm water overloads sewer mains and pushes up through the lowest drain in the house.
Roof leaks here come from summer downpours and, with about 99 freeze-thaw days a year, from winter ice dams. Most show up as ceiling stains in the room below.
27% of occupied homes in St. Lawrence County heat mainly with wood or propane, above the New York county median of 19%.
About 7 nights a year here stay at 65°F or warmer, so basements and crawl spaces can grow mold even without a leak.
Local risk profile
About 107,226 people live in St. Lawrence County, 2,680 square miles in northern New York, in roughly 51,970 homes. Canton is the county seat; Massena, Ogdensburg and Potsdam are the next largest communities. The county's median home was built in 1964.
55/100 Water Damage Risk Index: Elevated St. Lawrence County ranks 20 of 57 New York counties. See the statewide ranking and method.The three factors where St. Lawrence County ranks highest compared with other New York counties.
St. Lawrence is on the colder side of New York for pipes. It averaged 157 freezing nights a year over 2015–2024, 80 of them at 20°F or colder, cold enough for pipes in outside walls and crawl spaces to freeze. Among 57 New York counties that's 6th.
The longest cold spell was straight 32 days without the temperature rising above freezing, ending in March 2015. The coldest night reached about -27°F on February 14, 2016. Burst pipes usually show up when a spell like that breaks and the ice thaws.
Most freezing nights fall from November to April, peaking in January. Disconnect garden hoses and shut off outdoor spigots before the first hard frost, and keep the heat at 55°F or higher if you'll be away.
On average the first fall freeze arrives around Oct 13 and the last spring freeze around May 8.
St. Lawrence gets fewer downpours than most New York counties, but they still fill basements. About 4.5 days a year bring an inch or more (42nd of 57), most often in July, out of 40.7 inches of total precipitation. On August 10, 2024, 3.25 inches fell in a single day. Multi-day storms matter most for basements; the wettest three days on record here totaled 4.33 inches (through October 23, 2016).
About 99 days a year swing from below freezing at night to above freezing by day. Those freeze-thaw cycles feed ice dams on roofs, open cracks in foundations and driveways, and stress pipes that are already marginal.
Housing
Roughly 67% of the county's housing was built before 1980. That puts St. Lawrence near the middle of New York's 57 counties.
Older and newer homes sit side by side here: 47% predate 1960 and 14% are from 2000 or later. Corroded pipe is the typical failure in the first group, burst supply hoses in the second.
Here 10% of housing is manufactured homes. Check the skirting and the heat tape on the main water line every fall, because that one exposed line is what freezes.
The Census counted 20% of homes as vacant, above the New York county median of 13.9%. Empty houses are where a small leak turns into a large claim, because nobody is there to hear it.
Beyond water
Summer nights that don't drop below 65°F, a good marker of humid air, come about 7 times a year here, below the New York county median of 12. Mold grows when indoor humidity stays above about 60%, the EPA's ceiling. A basement dehumidifier set to 50% and drying anything wet within 24 to 48 hours prevents most problems.
Mold remediation: what to expectBy main heating fuel, St. Lawrence County homes break down as 34% utility gas, 13% electric, 16% propane and 11% wood. Wood heat is more common here than the state median. Have chimneys swept and fuel-burning appliances serviced each fall, and keep three feet clear around stoves and space heaters.
Fire and smoke cleanup: first stepsCoverage
Calls connect to restoration companies that work across St. Lawrence County. The largest communities by population:
Population from ACS 2020-2024 5-year estimates. Townships and unincorporated areas are covered too.
Nearby
Franklin, Hamilton, Herkimer and Lewis get more pipe-freeze nights than St. Lawrence. All of its neighbors see more heavy-rain days. Herkimer County has the oldest housing nearby, with 73% of homes built before 1980.
By the numbers
| Factor | St. Lawrence | New York median | Rank |
|---|---|---|---|
| Homes built before 1960 | 47% | 45% | 24 of 57 |
| Homes built before 1980 | 67% | 67% | 27 of 57 |
| Homes built 2000 or later | 14% | 13% | 23 of 57 |
| Manufactured or mobile homes | 10% | 7.6% | 17 of 57 |
| Vacant homes | 20% | 14% | 18 of 57 |
| Wood or propane heat | 27% | 19% | 13 of 57 |
| Nights at 20°F or colder | 80/yr | 55/yr | 6 of 57 |
| Days with 1 inch+ of rain | 4.5/yr | 6/yr | 42 of 57 |
| Freeze-thaw days | 99/yr | 101/yr | 31 of 57 |
| Muggy nights (65°F+) | 7/yr | 12/yr | 41 of 57 |
Rank 1 is the highest value. Bars run from the lowest to the highest New York county; the tick marks the median; orange means higher water damage risk than the median, green means lower.
Questions
Peak risk months in St. Lawrence County: freezing from November to April, heavy rain in June, July and October.
Sources: U.S. Census Bureau, ACS 2024 5-year estimates (2020-2024); weather from NOAA nClimGrid-Daily county averages (EpiNOAA), 2015–2024, averaged across the county; county boundaries from Census TIGER. Reviewed 2026-10-21. Methodology