What should a home buyer know about monsoon season in Scottsdale?

Monsoon storms can bring flash flooding, dust storms and damaging winds, and the National Weather Service has set the season as June 15 through September 30. For a buyer, that turns into four things you can look into before you buy: how water leaves the lot, whether a wash or drainage easement crosses it, what condition the roof and the trees are in, and whether the home is in a mapped floodplain.

I'm Jen Keene, a REALTOR® with eXp Luxury in Scottsdale, AZ, and I'm the agent people call at every stage of their life. I've put together what the National Weather Service in Phoenix, the Flood Control District of Maricopa County, the City of Scottsdale, the City of Phoenix and FEMA's FloodSmart.gov say about it, with the source named next to each fact.

This is general information, not legal, insurance or engineering advice. I checked each source on November 7, 2026, and I'm not predicting any storm or any season. A licensed home inspector, your insurance agent and the city or county staff named below can speak to the specific home you're looking at.

June 15 through September 30. The University of Arizona's Climate Assessment for the Southwest (CLIMAS) says the National Weather Service changed the start of the monsoon in 2008 from a date based on local conditions to a fixed June 15, with an end date of September 30. The East Valley Tribune reported the same announcement, and the City of Phoenix's monsoon page lists the same dates. Before the change, the Tribune says the start was counted from three straight days of dew points of at least 55 degrees.

Those dates are a calendar definition, so they tell you when the season is counted and nothing about what any one year will bring. One practical result for a buyer is that a home toured in the fall or winter shows you very little of how it handles a storm, which is why the walk-through questions in the next sections matter.

The National Weather Service office in Phoenix lists dust storms, downbursts and damaging winds, flash floods and lightning among the hazards on its monsoon safety page, and it calls this the most dangerous time of year for weather in the Southwest. The Tribune's report on the 2008 change quotes the Phoenix office's meteorologist in charge hoping people will focus on lightning strikes, dust storms, flash floods and punishing winds.

Flash floods are the one that connects most directly to a house and its street. The National Weather Service says never to drive into a flooded roadway because the depth is easy to misjudge and the road may be damaged under the water, and the City of Phoenix says two feet of rushing water can carry away most vehicles. For dust storms, both say to pull completely off the road and turn off your lights.

Start with how water moves across it. The City of Scottsdale's Homeowner's Guide to Drainage and the Flood Control District's flood-risk guide ask the same questions: Is any part of the house lower than the ground around it, so water can't flow away? Is there a natural wash, drainage channel or stormwater basin on or near the property? Is there a drainage easement? Can roof runoff flow safely away from the house? Both suggest looking for signs of flow, like erosion and debris, signs of ponding, like water-stained walls or overgrown vegetation, and drainage features like grates and drainpipes. The district's guide adds high-water marks on the house or property and reviewing the seller's disclosures about drainage and flooding.

To find out whether an easement exists, both guides say to check the recorded plat for the lot or subdivision, which shows the tracts and easements and describes what each is for and who maintains it, and to look at the deed and title for disclosures and restrictions. I'd ask your title company for the plat and the seller's disclosure early, and put anything unclear to your home inspector while you're still in the inspection period. I've written about how the inspection period works in Arizona.

The City of Scottsdale's guide also describes lots with a depressed area or a berm that is there to hold runoff from the roof, driveway and lot, and it says that storage capacity has to be kept if the yard is re-landscaped. If a yard looks oddly dished out, ask what it's for.

Usually the property owner. The City of Scottsdale says maintaining drainage facilities is generally the responsibility of the individual homeowner or the homeowners association, even when the facility sits in an easement dedicated to the city, while the city and the Flood Control District maintain certain larger regional facilities. The district's guide says that if a wash or drainage easement runs through your property, local stormwater ordinances require you to keep it free of obstructions so water can flow.

Both guides say a wash must not be filled in, blocked, diverted or altered, and that walls and fences should not cross one. For a buyer, that means a wall, a driveway or a backyard project built across a wash is worth a question to the seller and the city, because the city guide says permits are required for grading or structural work in a drainage easement. The recorded plat, the CC&Rs and the grading and drainage plan are where the city says to find out who is responsible for what on a particular lot.

It's an online map. The Flood Control District of Maricopa County invites you to use its GIS Floodplain Viewer to see the currently designated floodplains in the county, and the district's guide says to use it to find out whether a property is in a mapped 100-year FEMA floodplain. The guide also says the online maps are not official FEMA documents and can't be used for an official floodplain determination. For one of those, the district says it provides floodplain determinations at no charge, by form or by calling its floodplain staff, and it points residents of cities that run their own floodplain programs to their city's floodplain manager as well.

A clear result on the map is not the same as no risk. The district says floodplains and flood hazards exist in areas that haven't yet been documented by a floodplain study, and FEMA's FloodSmart.gov says there is still flood risk outside the high-risk areas on flood maps. Your lender uses FEMA's flood insurance rate maps to decide whether flood insurance is required, and I've covered that in whether you need flood insurance for a home in Scottsdale.

For the roof, look at how it sheds water as well as what it's made of. The City of Scottsdale's drainage guide says roofs generate a great deal of runoff and that when it can't flow away from the house it can pool and flood an entryway or patio, and the City of Phoenix's monsoon page tells homeowners to keep roof drains and scuppers clear and to make sure landscaping directs water away from the building. Ask the seller what they know about the roof's age and any repairs, and ask the inspector to look at roof drainage. I've written about what a general home inspection reports on, including when a roofing contractor is worth booking as well.

For trees, the National Weather Service says most people hurt in severe thunderstorms are injured by falling trees, flying debris or downed power lines, and the City of Phoenix tells homeowners to thin out trees and trim overgrown vegetation. When you tour, note any large or leaning trees near the house, the garage and the pool, and ask the seller who has maintained them.

A standard homeowners policy usually covers wind and hail damage from a covered cause, and it does not cover flood, so a home can need two separate answers from an insurance agent. The roof's age and condition can change the price or the coverage. I've covered all of that, with the sources, in my post on homeowners insurance when buying in Scottsdale, so I won't repeat it here. Ask for a quote on the specific address while you're still deciding on the house.

If you're looking at a home and want to know how to look up its records, here's how to look up Scottsdale property records, and here's my guide to buying a home in Scottsdale.

If you have a home in mind and want help working out what to ask, get in touch or call me at (480) 203-6605. For anything about a specific lot, the City of Scottsdale's stormwater staff and the Flood Control District's floodplain staff are the people to ask.