Flood Zones and Home Buying in Austin: Maps, Atlas 14 and Insurance Timing

Austin is a beautiful city of creeks, and every creek has a floodplain. The City’s Watershed Protection Department says about 10 percent of land in Austin is in the floodplain, subject to the dangers of flash flooding. Many homes in or near those areas are perfectly good places to live, but a buyer should know the risk before signing, not after the first big storm. Here is how to check.

Why the maps changed: Atlas 14

In 2018 the National Weather Service completed a historical rainfall study for Texas called Atlas 14. The City explains that it shows Central Texas is getting heavier rainfall and that severe flooding is more likely than previously thought. Austin’s current floodplain maps show where flooding is likely with 10.2 inches of rain in 24 hours; the updated maps will reflect flooding from almost 13 inches in some areas, the amount with a one percent chance of happening in any year, the so-called 100-year storm.

The City adopted updated floodplain regulations in November 2019 in response to Atlas 14, and it is remapping floodplains citywide. Until those studies are finished, the City says, its regulatory floodplain is based on the current FEMA 500-year floodplain. In practice that means a home can be inside the area the City regulates even if it sits outside an older FEMA 100-year zone.

What the 100-year floodplain means

The City defines the 100-year floodplain as land predicted to flood during a storm with a 1 percent chance of occurring in any given year, also called the 1 percent annual chance floodplain or base flood. It adds that areas within it may flood in much smaller storms as well. FEMA uses the 100-year floodplain to run the federal flood insurance program, and the City uses it to regulate development.

How to check a property

• Look the address up on the City’s floodplain maps at ATXFloodPro.com. The City says light blue areas are in the fully developed floodplain and subject to floodplain regulations, and darker blue areas to stricter rules.
• Read the seller’s disclosure notice for the flood questions described below.
• Ask whether the home has flood insurance now and request the policy details.
• Look for drainage easements on the survey.
• If in doubt, contact the City’s floodplain office, FloodPro.

What the seller must tell you

The Texas seller’s disclosure notice under Section 5.008 of the Property Code asks the seller to say whether they are aware of several flood-related conditions. They include present flood insurance coverage, previous flooding due to a reservoir failure or release, previous water penetration into a structure due to a natural flood event, and whether the property is wholly or partly in a 100-year floodplain, a 500-year floodplain, a floodway or a flood pool. A yes on any of these deserves a follow-up question during your option period.

Drainage easements

Many Austin lots carry drainage easements. The City says permanent structures are generally not allowed in them, including buildings, sheds, fences and pools, and that owners should avoid trees or heavy landscaping that could block water or limit the City’s access for maintenance. If you plan a pool or a fence, check the survey for easements first.

Remodeling in the floodplain

If you hope to renovate, know that the City’s floodplain rules limit how much work may be done on an existing building in the floodplain without bringing it into compliance with local regulations. Permit applications for a remodel, repair or alteration must include a cost estimate of all proposed work, and an owner doing the work must estimate labor as if they had hired someone. A big renovation plan can therefore trigger much larger requirements.

Flood insurance and the 30-day wait

Ask your homeowners insurer exactly what it covers for flooding; buyers near creeks often add a separate flood policy, and timing matters. Under federal rules at 44 CFR 61.11, a new National Flood Insurance Program policy normally takes effect at 12:01 a.m. on the 30th calendar day after the application and payment. There is an important exception for buyers: when flood insurance is first bought in connection with making a loan, coverage takes effect at the loan closing, provided the policy is applied for and paid at or before closing.

Situation	When NFIP coverage starts
Bought with a new mortgage, applied and paid by closing	At the loan closing
Bought later, for a home you already own	30th calendar day after application and payment
Within 13 months after a revised flood map takes effect	Day after application and payment

So the best moment to decide on flood insurance is before closing, not after you move in. The City notes that its floodplain work keeps Austin compliant with FEMA rules and gives residents access to more affordable, federally backed flood insurance.

Putting it together

Check the map, read the disclosure, look at the survey and price the insurance, all within your option period. For how the option period works, see Home Inspections in Texas: Licensed Inspectors, the Option Period and Repairs, and for the order of the whole purchase, Buying a Home in Austin, Step by Step: From First Budget to Keys.