Carrollton’s stormwater system includes natural floodplains, creeks, storm drains, and detention ponds that help manage rainwater. However, extreme rainfall can lead to localized flooding in some areas.

Key Drainage Facts

• The City maintains and manages 243 miles of underground stormwater pipes and 27 miles of drainage channels and creeks.
• There are four major drainageways across the city: Dudley Branch, Furneaux Creek, Hutton Branch, and Indian Creek.
• The Elm Fork of the Trinity River runs along the western boundary of the City.
• The Public Works Department regularly inspects and clears storm drains to prevent blockages.
• Flooding is partially buffered by Lake Lewisville, Lake Ray Roberts, and Lake Grapevine.
• These reservoirs are controlled by the U.S. Army Corps of Engineers to reduce peak flows into the Elm Fork of the Trinity River.

City Actions to Reduce Flooding

• Stormwater Improvement Projects – Upgrading drainage infrastructure
• Floodplain Regulations – Ensuring responsible development
• Flood Mitigation Initiatives – Conducting studies and drainage projects

Flood Safety & Preparedness

Before a Flood:

• Install flood barriers, sandbags, or sump pumps if needed
• Keep important documents in waterproof containers

During a Flood:

• Never walk or drive through floodwaters
• Evacuate if advised by emergency officials
• Stay tuned to Carrollton emergency alerts

How You Can Help

Residents can help by keeping storm drains clear of debris and reporting drainage issues to the Engineering Department at 972-466-3200.

Learn more on the Stormwater Quality page .

The Engineering Department oversees floodplain management, drainage infrastructure, and FEMA compliance.

What is Floodplain Management?

Strategies and actions that aim to reduce damage caused by floods, protect the natural function of floodplains, and use flood risk information to inform planning decisions.

Components of Floodplain Management

• Flood Hazard Identification and Mapping
• Regulatory Measures
• Structural Measures
• Non-Structural Measures
• Natural and Beneficial Functions

Goals of Floodplain Management

• Protect life and property
• Ensure public safety
• Minimize economic losses
• Preserve the natural environment

Channel Improvements

• Most channels in Carrollton have been improved using stone, concrete blocks, and concrete.
• These improvements have been permitted through the U.S. Army Corps of Engineers under Section 404 of the Clean Water Act .
• The Section 404 permit places restrictions on channel modifications and requires vegetation and stabilization standards.

Vegetation Impact on Floodplain Management

The City routinely analyzes channels, including vegetation along channel slopes, to determine flood elevations for design floods.

• Vegetation must consist of native species and is required to remain in place throughout channel areas.
• This vegetation helps protect erosive banks and supports wildlife habitat. It is also required under the Section 404 permit.
• Cutting or removal of this vegetation is not permitted under the federal requirements.

Planned and Ongoing Initiatives

• Stormwater Master Plan – Identifies future drainage improvements
• Floodplain Mapping Updates – Partnering with FEMA to update flood maps
• Emergency Management Operations – Rain gauge system for emergency alerts
• Community Rating System (CRS) Participation – Reducing flood insurance costs for residents
• Higher Standards Concept – Requires finished floors to be 2 feet above the 100-year floodplain. The National Flood Insurance Program (NFIP) requires 0.0 feet. It also requires no increase in offsite flood elevations (NFIP allows up to 1 foot increase).
• Corridor Development Certificate Program – Participation with the North Central Texas Council of Governments (NCTCOG) to limit development in the Trinity River basin and maintain manageable peak drainage flows.

For additional information, contact the City’s Floodplain Administrator, Matthew Brennan, P.E. at 972-466-3183.

Learn more at Corridor Development Certificate Program or National Flood Insurance Program (NFIP) .

An Elevation Certificate (EC) is an official document that provides elevation data about a structure relative to the Base Flood Elevation (BFE) established by FEMA.

What an Elevation Certificate is used for

• Determining flood insurance premiums under the National Flood Insurance Program (NFIP)
• Ensuring compliance with local building codes and floodplain regulations
• Supporting requests for flood zone changes, such as a Letter of Map Amendment (LOMA)

Why Property Owners Should Obtain an Elevation Certificate

Lower Flood Insurance Costs

• Properties above the Base Flood Elevation (BFE) may qualify for reduced flood insurance rates
• Elevation data helps insurers determine risk and can result in lower premiums

Correcting Flood Zone Designations

• Elevation certificates can support a Letter of Map Amendment (LOMA) request to FEMA
• If approved, this may remove mandatory flood insurance requirements

Real Estate and Property Transactions

• Clear documentation of flood risk supports property sales
• Having an EC available helps avoid delays during closings

Construction and Compliance

• New construction and major renovations must meet flood elevation requirements
• An EC verifies compliance with Carrollton floodplain regulations

Flood Protection Planning

• Elevation data helps guide floodproofing and mitigation decisions
• Properties below BFE may require additional protective measures such as elevating systems or installing barriers

How to Obtain an Elevation Certificate

Step 1: Check Existing Records

• The City of Carrollton may already have an elevation certificate on file
• Contact the Engineering Department to confirm availability

Step 2: Hire a Licensed Professional

• If not available, hire a Texas-licensed land surveyor, engineer, or architect

Helpful Resources

• Texas Society of Professional Surveyors – Find a Certified Surveyor
• FEMA Elevation Certificate Form and Instructions

Step 3: Submit for Insurance or Map Changes

• Submit the EC to your insurance provider to determine potential premium reductions
• If needed, use it to support a FEMA Letter of Map Amendment (LOMA) request

Carrollton follows FEMA’s Flood Insurance Rate Maps (FIRMs) to determine flood risk zones. Use the interactive FEMA flood map to check if your property is in a flood-prone area.

Floodplain Definitions

• 100-Year Floodplain (High-Risk Areas – Zone A, AE, AO): 1% annual chance of flooding
• 500-Year Floodplain (Moderate-Risk Areas – Zone X Shaded): 0.2% annual chance of flooding
• Minimal Risk Areas (Zone X Unshaded): Areas outside high-risk flood zones

Find Your Property’s Flood Zone

View the Interactive FEMA Floodplain Map