Probably some, yes. The Flood Control District of Maricopa County says every property in the county is at some risk, even outside mapped floodplains, and one in four flood claims come from outside them. Check your flood zone, buy flood insurance early because it has a 30-day wait, and protect your drains.
How likely is a flood outside a floodplain?
More likely than most owners assume. The district says one in four flood insurance claims nationally are for properties in areas outside the mapped FEMA 100-year floodplains. A floodplain map only shows where a set of flood-study results puts the line. It doesn't promise your street stays dry when a storm parks over it.
The National Weather Service adds why monsoon storms are so hard on the ground. Its Phoenix office notes that flash flooding "can occur many miles away from the thunderstorm as the runoff flows into the valleys and deserts." A storm over the mountains can send water toward a neighborhood that saw no rain.
Signs your property may take water
The district lists what to look for on and near your lot:
- A natural wash or man-made drainage channel on or near your property.
- A dedicated drainage easement on or near your property.
- Evidence of flow (erosion, debris), pooling or ponding, such as overgrown vegetation or water-stained walls.
- Drainage features such as grates or drainpipes on your property.
If you see any of those, treat the lot as flood-prone whatever the map says.
How to check your flood zone
Your lender uses FEMA's Flood Insurance Rate Map (FIRM) to decide whether your property sits in a 100-year floodplain. The Flood Control District will look up your zone for you. You fill out its Flood Hazard Information Request Form, and the district says there is no fee for floodplain determinations. If you're in a regulated 100-year floodplain and have a federally backed mortgage, you're required to buy flood insurance.
Does homeowners insurance cover a flood?
Usually not. The district states plainly: "Flood damage is not covered by homeowners' insurance policies." FEMA says the same, that most homeowners insurance does not cover flood damage, and that flood coverage is a separate policy.
Timing matters. FEMA says there is typically a 30-day waiting period before a National Flood Insurance Program policy goes into effect, unless the coverage is required by a government-backed lender or tied to a community flood map change. The district's advice is short: when a storm is in the forecast, it's too late to get a flood policy.
Where plumbing fits in
Flooding is a drainage and water-damage problem before it is a plumbing problem, but your plumbing is where the storm shows up inside the house. Heavy rain can surcharge the city sewer and push water up through the lowest drains, and why drains back up during monsoon explains how. A backwater valve guards the low fixtures, and when code requires one depends on where your fixtures sit compared to the next upstream manhole. Our monsoon season plumbing overview covers the rest of what a wet summer does to slab and sewer lines.
If a flood does reach the house, the first hour matters. The sequence is in what to do first after a flood or major water leak.
HQ can camera-inspect your sewer line and check whether a backwater valve makes sense for your house. We offer free estimates and upfront pricing.