Key facts: San Antonio
Why creeks rise so fast
Rock and thin soil shed water quickly. A flood in 1921 led to the Olmos Dam, and the River Walk tunnel now carries floodwater under downtown.[1] Low-water crossings remain the danger, so turn around.
Limestone, clay and slabs
Soil here moves with moisture, and that stresses foundations and buried lines. After a long dry spell, a sudden leak is common.
Flood claims recorded in Bexar County
San Antonio sits in Bexar County. FEMA publishes every National Flood Insurance Program claim with personal details removed, which gives a plain record of where water has reached insured buildings here.
| Measure | Count |
|---|---|
| Flood insurance claims on record | 2,309 |
| Year with the most claims | 1998 (412) |
| Largest named event | Flooding (591) |
| Claims outside high-risk A and V zones | 56% |
| Claims on buildings built before 1975 | 62% |
County-wide counts of insured claims only. Uninsured losses, burst pipes and appliance leaks are not in this data.
What the San Antonio claim record shows
For San Antonio homes, the local precedents are the events behind the most Bexar County claims: Flooding (591 claims), Torrential Rain (236 claims) and Tropical Storm Erin (50 claims).
About 56% of claims with a recorded zone came from outside the high-risk A and V zones, so a moderate-risk label does not mean a San Antonio home stays dry.
If your San Antonio home is older, note that buildings from before 1975 make up 62% of county claims with a known build date. Many predate current flood maps, so inspect low outlets, ductwork and subfloors closely after any water event.
Federal disaster history for Bexar County
FEMA lists 32 federal declarations covering Bexar County. The most common types are hurricane (12), fire (8) and flood (5). The latest are Severe Storms, Straight-Line Winds, Tornadoes, and Flooding in 2026, Flooding in 2026 and Duke Fire in 2025. Federal aid can open after a declaration, so San Antonio owners should look it up before discarding damaged items.
San Antonio weather and your home
Weather records for San Antonio from 2015 through 2024 average 39 inches of precipitation a year, and May and April are the wettest months. The area averages 8.0 days a year with an inch or more.
Freezing nights are rare, at about 6 a year in San Antonio, so the bigger concerns are storms, plumbing failures and humidity.
With about 107 days a year at 90°F or hotter, San Antonio air conditioners run hard, and a clogged condensate line can soak a ceiling without warning.
When rain falls in San Antonio
Seasonal averages for San Antonio, 2015 through 2024. Plan roof, gutter and sump pump checks before the wettest stretch.
| Season | Average | Share of year |
|---|---|---|
| January to March | 6.8 in | 17% |
| April to June | 13.7 in | 35% |
| July to September | 9.7 in | 25% |
| October to December | 8.9 in | 23% |
Modeled from Open-Meteo historical weather data. Precipitation includes rain and melted snow.
San Antonio home checklist from these records
- Don't rely on recent quiet years. Only 16% of Bexar County claims date from 2015 or later, so older floods still show what can happen.
- Check roof flashing and drains before May, the wettest month in San Antonio.
- Clear the air conditioner drain line before the 107 days of 90°F heat begin.
- Keep dated photos of each room. After Flooding, 591 insured Bexar County owners filed claims at about the same time.
What to tell the San Antonio contractor
- Your nearest creek
- Whether a low-water crossing is closed
- Whether the slab is wet
Services San Antonio callers ask about
Questions
San Antonio water damage questions
Is San Antonio flood-prone?
Yes, especially near creeks and low crossings.
What about the 2021 freeze?
It split many exposed lines, so insulate before winter.