Fort Bend Subsidence District vs. Harris Galveston: A Developer’s Guide to Houston’s Competing Groundwater Rulebooks

Why are there two subsidence districts?

The Legislature created them 14 years apart to fight the same problem. It created HGSD in May 1975 to stop subsidence caused by groundwater pumping, and HGSD's history page calls it the first political subdivision of its kind in the United States. Its work covers Harris and Galveston counties.

The Legislature created FBSD in 1989 to regulate groundwater withdrawal within Fort Bend County, as FBSD's mission page describes.

Both use the same basic tool. They cap groundwater as a share of each permittee's total water demand and push users toward alternative supply, mostly surface water. That shared approach is why developers assume the rules are interchangeable. They are not. Each district sets its own areas, limits, schedule and permit process.

How do you confirm which district governs a site?

Start with the county, then check the parcel against the district's regulatory area map. HGSD covers Harris and Galveston counties and FBSD covers Fort Bend County, so the Harris and Fort Bend county line divides them. Each district also splits its territory into regulatory areas, and the area drives the numbers.

Take extra care with a tract that crosses the county line, or a site in a neighboring county, which may fall under neither district. Do the check during a utility feasibility study, before closing, not after infrastructure planning starts.

What does HGSD require today?

HGSD limits groundwater to a share of each permittee's annual total water demand, by regulatory area. HGSD's Regulatory Plan was approved January 9, 2013, and amended April 14, 2021. It sets these limits:

• Area 1: groundwater no more than 10% of annual total water demand
• Area 2: no more than 20%
• Area 3: no more than 20%, unless the permittee operates under a certified groundwater reduction plan (GRP)
• Area 3 GRP permittees: no more than 40% beginning with permits issued in 2025, and no more than 20% beginning with permits issued in 2035

HGSD says its most recent plan review was completed in 2025. Pumping above a permit limit draws a disincentive fee in each permit year the reduction is not met, and HGSD's disincentive fee FAQ lists GRPs and groundwater credits among the ways to avoid it.

What does FBSD require after its 2025 plan?

FBSD moved Area A's next deadline to 2030 and, for the first time, set a schedule for Area B. FBSD's announcement says its board adopted the new regulatory plan on December 10, 2025, after a joint review with HGSD of population, water demand and subsidence that began in 2020. FBSD's regulatory areas page now shows:

• Area A: groundwater no more than 40% of total water demand for permits beginning January 1, 2030 (the date was January 1, 2027 before the change)
• Area B, not in a GRP: no more than 40% of the permittee's total water demand for permits beginning January 1, 2035
• Area B, in an approved GRP: no more than 70% of the group's total water demand for permits beginning January 1, 2050

Area B had no conversion requirement before this plan. A cost estimate or water supply plan that assumed Area B was exempt needs a second look.

Why don't the numbers transfer between districts?

Because the same percentage lands on a different date on each side of the line. HGSD Area 3 GRP permittees are at 40% now and go to 20% with 2035 permits. FBSD Area A reaches 40% in 2030, and Area B GRP groups reach 70% in 2050. A plan built on one district's schedule will be wrong in the other.

In both districts, GRP membership changes the limit. In HGSD Area 3, a permittee outside a GRP is already held to 20%. In FBSD Area B, a permittee outside a GRP reaches 40% fifteen years before GRP groups face their 70% limit. Whether a project can join an existing GRP is often the first water supply question.

How do well permits differ between the districts?

Each district runs its own permit process under its own rules. FBSD's FAQ says most water wells in Fort Bend County have needed permits since 1989. It excludes some wells, such as a well serving only a single-family home with a casing of five inches or less, drilled before 2015.

HGSD issues its own permits under its own rules. Do not carry a well design, pumping allocation or permit approach from one county to the other. Confirm the current rules for the specific well location with the district that governs it.

Who supplies the surface water on each side of the line?

Usually a regional water authority or a city, and the provider depends on location. In north Fort Bend County, the Legislature created the North Fort Bend Water Authority in 2005 to help its members meet FBSD's groundwater reduction rules. A 2015 Senate bill analysis put its membership at about 69 water districts, the City of Fulshear and a small part of Katy.

Harris County has its own providers. Confirm which provider serves the site, whether it has capacity, and what its contract requires. Do not assume conversion infrastructure or contract terms from a Harris County project will look the same in Fort Bend.

How should a MUD plan capital work across district lines?

On two clocks, one per district. A MUD or developer with service areas in both districts needs each district's timeline and infrastructure tracked separately. The two schedules affect bond timing, financing and construction sequencing.

Across a portfolio, treat district confirmation as a site-by-site item. Two sites a few miles apart can sit on different schedules. A quick readiness check:

1. Do you know which district, and which regulatory area, each parcel sits in?
2. Have you read that district's current plan, including FBSD's December 2025 changes?
3. Do you know whether the project can join a certified or approved GRP?
4. Is a surface water provider identified, with capacity confirmed?
5. Does the capital plan follow that district's dates rather than the other district's?

If any answer is no, the water supply plan is not ready for a land decision. Take the open items to your engineer and the district.

Limits of this article. This summarizes each district's published plan as of October 2026 for general education. Both districts review their plans and rules, so confirm current requirements with the district before you rely on them.

Frequently asked questions

How do we confirm which subsidence district governs a site near a county line?

Check the parcel against each district's published boundary and regulatory area maps, then confirm with the district. A general sense of where the site is in the Houston region is not enough.

If a development spans both districts, does it need two compliance strategies?

Generally yes. Each district regulates independently, so the part of the project in each district has to meet that district's rules and schedule.

Is Fort Bend's program less strict than Harris-Galveston's?

Not uniformly. The limits and dates differ by district and by regulatory area, and FBSD Area B now has requirements it did not have before 2025. Compare the specific areas that apply to your sites.

I'm a developer under contract on a tract in FBSD Regulatory Area B, and our old water study says Area B has no groundwater reduction requirement. Is that still true?

No. FBSD's December 2025 plan added Area B limits for permits beginning in 2035 and 2050. Ask your engineer to update the study against the current plan before you close.

I sit on a MUD board in FBSD Regulatory Area A and our engineer's schedule still shows a 2027 conversion deadline. What changed?

FBSD moved the Area A date to permits beginning January 1, 2030, with groundwater held to 40% of total water demand. Update the capital plan and bond schedule to the new date.

Related resources

• Groundwater Reduction Plans: What the Harris Galveston Subsidence District Requires Before You Drill a Well
• Municipal Utility Districts in Houston Suburbs: When to Form One
• CCN Disputes in West Houston
• San Jacinto River Authority Surface Water Conversion Contracts

Weighing groundwater rules across Fort Bend, Harris and Galveston sites?

We check which district and regulatory area governs each site and build the water supply plan around that district's current dates, before you commit to land or infrastructure.

Talk to an engineer about your site

We specialize in:

• Water supply due diligence before land acquisition
• Utility feasibility studies
• Groundwater permit and conversion planning
• Surface water connection and conversion infrastructure design
• Public water system design
• MUD capital improvement planning

Modern Engineering Solutions, McKinney, Texas. Contact: (214) 833-6748 or mod-eng.com