Key facts: Riverside
- The Santa Ana River has a long flood history here, including the great 1938 flood, and Prado Dam near Corona was built soon after.[1]
- Washes look harmless most of the year, then run hard during atmospheric rivers.
- Keep out of channels, and check drainage around your yard before winter.
Dry channels that fill
Washes look harmless most of the year, then run hard during atmospheric rivers. Keep out of channels, and check drainage around your yard before winter.
Hot-climate plumbing
Heat, hard water and ground movement wear on fittings. Many tract homes are now old enough for their original water heaters and lines to need checking.
Flood claims recorded in Riverside County
Riverside sits in Riverside 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 | 1,636 |
| Year with the most claims | 1980 (340) |
| Largest named event | Flooding (218) |
| Claims outside high-risk A and V zones | 59% |
| Claims on buildings built before 1975 | 46% |
County-wide counts of insured claims only. Uninsured losses, burst pipes and appliance leaks are not in this data.
What the Riverside claim record shows
For Riverside homes, the local precedents are the events behind the most Riverside County claims: Flooding (218 claims), Tropical Storm Hilary (60 claims) and Pineapple Express - Southern (41 claims).
About 59% 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 Riverside home stays dry.
A newer Riverside home is not exempt: 54% of claims with a known build date involved homes built in 1975 or later.
Federal disaster history for Riverside County
FEMA lists 66 federal declarations covering Riverside County. The most common types are fire (38), flood (13) and severe storm (7). The latest are Bain Fire in 2026, Airport Fire in 2024 and Hawarden Fire in 2024. Federal aid can open after a declaration, so Riverside owners should look it up before discarding damaged items.
Riverside weather and your home
Weather records for Riverside from 2015 through 2024 average 15 inches of precipitation a year, and January and March are the wettest months. The area averages 3.0 days a year with an inch or more.
Freezing nights are rare, at about 2 a year in Riverside, so the bigger concerns are storms, plumbing failures and humidity.
With about 100 days a year at 90°F or hotter, Riverside air conditioners run hard, and a clogged condensate line can soak a ceiling without warning.
When rain falls in Riverside
Seasonal averages for Riverside, 2015 through 2024. Plan roof, gutter and sump pump checks before the wettest stretch.
| Season | Average | Share of year |
|---|---|---|
| January to March | 8.5 in | 58% |
| April to June | 1.4 in | 9% |
| July to September | 0.9 in | 6% |
| October to December | 3.8 in | 26% |
Modeled from Open-Meteo historical weather data. Precipitation includes rain and melted snow.
Riverside home checklist from these records
- Don't rely on recent quiet years. Only 12% of Riverside County claims date from 2015 or later, so older floods still show what can happen.
- Check roof flashing and drains before January, the wettest month in Riverside.
- Clear the air conditioner drain line before the 100 days of 90°F heat begin.
- Keep dated photos of each room. After Flooding, 218 insured Riverside County owners filed claims at about the same time.
What to tell the Riverside contractor
- Your city
- Whether a wash is nearby
- The age of your water heater
Services Riverside callers ask about
Questions
Riverside water damage questions
Do you cover Corona?
Yes, along with Moreno Valley and Menifee.
Why is my slab wet?
It could be a line, drain or outside water, so a plumber should confirm.