Blog · October 14, 2026 · Pennsylvania
Reading the Brentwood Flood Zone Map for a parcel
Flood zones are set by FEMA, and checking one near Pleasant Hills takes a few minutes.
Main page: Allegheny County, PA GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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Ahead of any purchase around Whitehall, pull up the Brentwood flood zone map: the zone on that map shapes insurance, building rules and resale. Covered here for Brentwood: locating a parcel on FEMA's map, reading the zone codes, and matching it with the county parcel viewer.
Checking the Brentwood flood zone map step by step
Start with FEMA's Flood Map Service Center: search an address around Mount Oliver, then open the map view for that panel. A tract near Castle Shannon without an address can still be found: pan from the closest town and click the spot.
The free map to start with
Begin with the Allegheny County ArcGIS parcel map; it includes each assessed parcel in the county, Mount Oliver included. For acreage around Baldwin, type a street address, an owner's name or a parcel number, and the viewer zooms to the match. If you're looking near Dormont, a pop-up or side panel usually lists the owner of record, assessed acreage, a parcel ID and sometimes recent sales.
Using it on a phone
The parcel map usually runs in a mobile browser, handy when you're parked on a road near Mount Oliver, though signal can drop in rural spots. A printout of the tract near Pleasant Hills is a good backup.
Legal descriptions in Pennsylvania
Tracts outside towns near Castle Shannon are often described by metes and bounds, which trace the boundary call by call. Subdivision lots in Whitehall are typically described by lot and block, making them easier to find. Write down the legal description for the tract near Whitehall when you talk to a surveyor.
What to request from a seller
Request about past flood claims for the house near Castle Shannon; getting a quote early avoids surprises.
Where Brentwood fits in
Brentwood sits in Allegheny County, Pennsylvania, so its parcels are on the county's map. For a parcel near Baldwin, the municipality handles things like zoning, permits and utilities within town limits, and the county still keeps the parcel and deed records. Lots just outside the town limits out by Whitehall usually falls under county rules instead.
What the zone letters mean
On ground around Mount Oliver, zones beginning with A or V mark the Special Flood Hazard Area, meaning a 1% or greater chance of flooding each year. With a lot near Mount Oliver, minimal risk is not no risk: according to FEMA, floods happen outside mapped zones too.
Matching the zone to the lot lines
FEMA doesn't draw property lines, so check the Allegheny County ArcGIS parcel map too to see exactly which lot near Mount Oliver you're looking at.
A quick look at the area
Pittsburgh serves as the county seat, which is where the courthouse records live. You'll also find Whitehall, Baldwin, Castle Shannon, and Mount Oliver. Around 1,224,825 people live in Allegheny County (Census Bureau estimate, 2023) on roughly 730 square miles. Allegheny County was organized in 1788, which matters when you trace an old farm's title. Places such as Allegheny River and Monongahela River are easy to spot when you zoom out from Castle Shannon.
Who handles what
If the acreage or value on a parcel near Castle Shannon looks off are handled by the county assessment office, the office behind the parcel record. Building or septic questions for a lot near Mount Oliver are for the local planning and health departments, and the answer depends on jurisdiction.
Beyond the mapped zones
Small streams around Baldwin aren't always studied in detail, so look for water marks and debris lines. Wetlands near Castle Shannon can limit building even outside a flood zone; check the National Wetlands Inventory mapper for a first look.
The paper trail behind a parcel
Before you sign anything, pull the recorded deed from the Recorder of Deeds; the parcel line is a drawing of it, and that holds around Whitehall too. Long-held tracts around Pleasant Hills can go back through several deeds, and a title company can sort it out on a real sale.
What a flood zone means for a buyer
For a structure inside an A or V zone and a federally regulated lender is involved, the lender will require flood insurance in communities in the NFIP, and that holds around Pleasant Hills too. New construction in a floodplain near Dormont can trigger elevation rules; check with the county or town building office early.
Questions about the Brentwood flood zone map
What is a LOMA around Dormont?
It depends, but FEMA's LOMA process is the usual route when a building near Dormont sits above the base flood elevation; it starts with an elevation survey.
What does an AE label mean for a lot near Castle Shannon?
In most cases, AE is a Special Flood Hazard Area with a published base flood elevation, which shapes building rules near Dormont.
How often are flood maps updated around Baldwin?
Good question; a new study can move a zone line near Pleasant Hills, so look at the panel date.
What is a base flood elevation near Castle Shannon?
It depends, but the base flood elevation is the water level expected in the 1% annual chance flood; surveyors near Mount Oliver use it often.
What's the tax parcel number used for around Baldwin?
It's the number the county assessment office uses to track a tract near Whitehall; you'll see it in the viewer and on tax statements.
Open the official Allegheny County, PA parcel map See it in the Platbookmapper directory
Not a survey. County GIS and tax parcel maps are assessment and planning layers. They are not a substitute for a recorded plat, deed, or licensed survey, especially for fences, setbacks, or boundary disputes.