Cypress, TX · Subsidence, taxes & permits
Is Cypress, TX Sinking?
Yes — and the honest version of that answer is more useful than the alarming one. What subsidence actually does, what it doesn't do, and the two Cypress questions that cost real money.
The short answer
Cypress is sinking at more than 1.5 centimetres a year, according to the Harris-Galveston Subsidence District's 2025 annual report. Northwest Harris County is now one of the most active subsidence areas in the region, because groundwater pumping has drawn the Chicot and Evangeline aquifers down by more than 300 feet in places and the sediments compact as it goes.
That is a real, measured, ongoing phenomenon. It is also almost certainly not the thing you should be worried about when you buy a house here — and the reason why is the useful part.
What subsidence does not do
Search this topic and you will find page after page implying that subsidence is why Houston-area slabs crack. It isn't, and the arithmetic is not close.
Regional subsidence lowers a wide area gradually and fairly uniformly. Spread across kilometres, the differential over the sixty-foot footprint of a house is negligible. Uniform settlement of a whole district does not crack a slab.
What actually moves your foundation is clay
Gulf Coast soils are expansive: they swell when saturated and shrink in drought, and that cycle lifts and drops the perimeter of a slab. The Texas Department of Licensing and Regulation identifies expansive soils as a very common cause of foundation problems, noting shrink-swell damage affects roughly 25% of all structures nationally and causes greater financial losses than earthquakes, floods, hurricanes and tornadoes. This is why watering your foundation through a Houston drought is genuinely worth doing — and why worrying about subsidence instead is worrying about the wrong thing.
I price foundation work, so I would rather tell you which of the two you are actually looking at than let you pay for a scare.
What subsidence does do — and it matters
1. It changes your flood picture
Ground that drops moves you lower relative to sea level and relative to areas sinking more slowly. Drainage was engineered for a particular set of elevations; change the elevations and you change the gradients. The Subsidence District lists changed drainage patterns and increased flooding directly among subsidence impacts. This is the genuine homeowner consequence, and it means the subsidence question and the flood question are really one question.
Which is also why the map vintage matters: Harris County's flood maps are being rebuilt for the first time since 2007. What the draft 2026 maps change.
2. Differential movement and faults
Uniform sinking is largely harmless to a structure. Uneven movement between adjacent areas is not — it is what cracks pipelines, roads and, occasionally, buildings. Northwest Harris County has documented active surface faults, including the Hockley Fault system, and fault movement here is associated with groundwater withdrawal. A house sitting on an active trace is a real structural question. It is also a site-specific one, which means it is checkable before you commit rather than discoverable afterwards.
Two things I am deliberately not going to tell you, because I could not verify them to a standard I would want to be held to: what subsidence does to your homeowner's insurance, and whether it measurably affects resale value. I have seen both asserted confidently online without a source behind them. If either matters to your decision, ask me and I will find out properly rather than guess.
Who is fixing it, and what it costs you
The Harris-Galveston Subsidence District was created in 1975 and regulates groundwater withdrawal by permit across three regulatory areas. Cypress is in Regulatory Area 3, where permit holders operating under a certified groundwater reduction plan are capped at 40% groundwater from 2025 and 20% from 2035.
Complying means building surface-water supply, and the numbers are large. The North Harris County Regional Water Authority has put its 60% conversion benchmark at roughly $2 billion, not expected complete before 2031, with full conversion estimated near $10 billion.
This is already on your tax bill
That infrastructure is funded partly through MUD “contract tax” line items. Harris County MUD 501, which serves Towne Lake, levies $0.39 per $100 as contract tax — about two thirds of its entire 2025 rate of $0.5972. So when you compare two Cypress MUD rates and one looks inexplicably higher, water conversion is frequently the explanation. It is not a hidden fee. It is just one nobody explains.
The two Cypress questions that actually cost money
Which MUD is the address in?
Cypress is unincorporated, so there is no city tax — but there is a municipal utility district, and dozens of them serve the area at genuinely different rates. Verified examples: Harris County MUD 249 at $0.71, MUD 501 (Towne Lake) at $0.5972, MUD 489 (Bridgeland) at $0.91. The realistic spread runs from about $0.60 to around $0.95 per $100.
On a $500,000 house, the gap between the bottom and top of that range is about $1,550 a year. Two houses five minutes apart, same price, same floor plan. Nobody mentions it at the showing.
Newer districts sit high because they carry fresh bond debt against a thin tax base, and they come down as the district builds out — MUD 489 has fallen from $1.00 to $0.91, MUD 249 from a $1.20 peak to $0.71. So the question is not only what the rate is today but where the district is in its life.
Look it up on HCAD by address — the account page lists every taxing jurisdiction on the parcel. Under Texas Water Code §49.452 you are also entitled to written notice at contract stating the district, its rate and its bonded debt. It is one page. Read it.
Who permits the work?
Harris County, not a city — through the Office of the County Engineer's Permits Division. If you are planning an addition, a garage conversion or a pool, that is where it goes, and the process is not the City of Houston process.
There is a genuine legal wrinkle here that I would rather flag than paper over: Cypress sits inside Houston's extraterritorial jurisdiction, and the Local Government Code contains a provision under which a municipality's adopted building code can control within its ETJ. Whether that alters the county requirement for a particular remodel is a question I call the county about on live projects rather than extrapolate. Anyone who gives you a confident blanket answer on that has probably not read the statute.
What this means if you are buying in Cypress
Cypress is a good place to buy. Roughly 200,000 people live across 77429 and 77433, and Bridgeland alone is planned for 20,000 homes and around 70,000 residents at buildout in the late 2030s. None of what is above is a reason to avoid it.
It is a reason to ask four questions before you write an offer:
- Which MUD is this parcel in, what does it levy, and where is it in its bond cycle?
- What is the flood designation on the current map and the draft 2026 map?
- Has the foundation moved, and is what I am seeing clay behaviour or something site-specific?
- Is any work on this house unpermitted, and what does the county say about putting it right?
I can answer all four for a specific address, usually the same day, and there is nothing to sign to ask.
Questions people actually ask
Is Cypress, TX sinking?
Yes, measurably — and northwest Harris County is now one of the more active areas in the region. The Harris-Galveston Subsidence District's 2025 annual report puts the Cypress and Tomball areas at more than 1.5 centimetres a year, roughly six tenths of an inch. Nearby continuous GPS stations run higher still: Katy at 2.64 cm/yr, with about 35 cm of cumulative movement since 2007. Site measurements in northwest Harris County include 61.2 cm between FM 1960 and Windfern Road since 1999, and 20.7 cm on Ash Green Drive since 2011. That is real, it is documented, and it is worth understanding properly rather than panicking about.
Why is it sinking?
Groundwater withdrawal. Pumping water out of the Chicot and Evangeline aquifers lowers pore pressure, the fine-grained sediments compact, and the ground surface drops. Water-level declines exceed 300 feet in parts of northern Harris County. The mechanism is well established and it is the reason a regulator exists for it at all.
Is subsidence why houses in Cypress get foundation problems?
No — and this is the part almost every article gets wrong. Regional subsidence lowers a broad area gradually and fairly evenly. Across the sixty-foot footprint of a house slab, the differential is negligible. It is not what cracks your foundation.
What does crack it is expansive clay. Gulf Coast clay soils swell when wet and shrink in drought, and that cycle moves slabs. The Texas Department of Licensing and Regulation calls expansive soils a very common cause of foundation problems and notes that shrink-swell damage affects about 25% of all structures nationally, with greater financial losses than earthquakes, floods, hurricanes and tornadoes combined. That is why foundation watering during a Houston drought is genuinely worth doing and subsidence worry is not.
So does subsidence matter to me as a buyer at all?
It matters, but through a different door than people expect. Two ways.
Flood risk and drainage. Sinking ground lowers you relative to sea level and relative to areas sinking more slowly. Drainage gradients were engineered at a particular elevation; when the elevation changes, the gradient changes. The Subsidence District lists changed drainage patterns and increased flooding among the direct impacts. This is the real link, and it is why the flood question and the subsidence question are the same question.
Active surface faults. Northwest Harris County has them — the Hockley Fault system is documented in the literature and fault movement is associated with groundwater withdrawal. Uniform sinking is largely harmless to a structure; differential movement is not. A house sitting on an active fault trace is a genuine structural question. That is site-specific, and it is checkable before you buy.
Is it getting better or worse?
Both, depending on where you look, and the direction of travel is the interesting part. The severe historical subsidence was in southeast Harris County and around the Ship Channel — as much as ten feet by 1979 — and regulation largely stopped it there. The active zone has since migrated north and west, which is where Cypress is. A 2025 review by Subsidence District and University of Houston researchers found the area sinking faster than 2 cm a year has shrunk to roughly one twentieth of its 1990 extent, but what remains is concentrated in Katy, Jersey Village and The Woodlands. Regionally, much better. Locally, this is now the front line.
What is being done about it, and does it cost me anything?
The Harris-Galveston Subsidence District, created in 1975, regulates groundwater by permit across three regulatory areas. Cypress sits in Regulatory Area 3, which caps groundwater at 40% of total demand from 2025 and 20% from 2035 for permit holders with a certified groundwater reduction plan. Meeting that means building surface-water infrastructure, and it is not cheap — the North Harris County Regional Water Authority has estimated its 60% benchmark at around $2 billion and does not expect to complete it before 2031.
That cost reaches you through water bills and through MUD “contract tax” line items. It is not abstract: Harris County MUD 501, serving Towne Lake, levies a $0.39 per $100 contract tax — about two thirds of its entire 2025 rate. When you compare MUD rates between two Cypress addresses, this is often what you are actually looking at.
Is Cypress a city? Is it part of Houston?
Neither. Cypress is unincorporated Harris County — no city government, no city council, no city property tax. It sits entirely inside the City of Houston's extraterritorial jurisdiction but is not in the city limits and Houston does not tax it. Law enforcement comes from the Harris County Sheriff's Office and Constable Precincts 4 and 5. Compare that with Jersey Village a few minutes away, which is an incorporated city with its own tax rate, police force and permit office. Same corner of the county, completely different governance.
Who issues permits for an addition in Cypress?
Harris County, through the Office of the County Engineer's Permits Division — not a city. The county permits residential construction, on-site sewage, water wells, driveways and pools, and it has enforced residential construction permitting for years.
I will be straight with you about the edge of my knowledge here: because Cypress sits inside Houston's ETJ, there is a provision in the Local Government Code under which a municipality's adopted building code can control within its ETJ. Whether that changes what the county requires for a specific remodel or addition in Cypress is a question I would call the Harris County Permits Division about rather than guess at — and I do call, on projects I am pricing. What I can tell you is that the answer is different from the City of Houston answer, and assuming otherwise is how people end up with unpermitted work they have to disclose later.
What is the property tax rate in Cypress?
There is no single answer, because the MUD is the variable. For 2025 the fixed pieces are Harris County at $0.38096, the Flood Control District at $0.04966, the Hospital District at $0.18761 and the Port of Houston Authority at $0.00590, plus the school district at $1.0669. Those sum to roughly $1.69 before your MUD.
Add a MUD and the total lands somewhere around 2.3% to 2.7% of assessed value — with the spread depending almost entirely on which district you are in. Treat that range as arithmetic from published individual rates rather than a figure any authority publishes, and note it excludes emergency services and community college districts that apply to some parcels.
How do I find out which MUD an address is in, and what it charges?
Dozens of municipal utility districts serve Cypress and the rates are genuinely far apart. Verified examples for recent years: Harris County MUD 249 at $0.71, MUD 501 (Towne Lake) at $0.5972, and MUD 489 (Bridgeland) at $0.91. Rates broadly run from about $0.60 to around $0.95 per $100, though I have sampled districts rather than all of them.
The authoritative per-address answer is HCAD — look up the property and the account page lists every taxing jurisdiction on it. The TCEQ water districts map viewer and the county GIS MUD layer will also show you boundaries. And under Texas Water Code §49.452 you are entitled to a written notice at contract stating the district, its rate and its bonded debt. Read it rather than initialling it.
Why is one Cypress MUD so much more expensive than the one down the road?
Bond debt and how built-out the district is. A new district borrows to build water, sewer and drainage before there are many houses to spread the cost across, so its rate starts high and falls as the tax base fills in. You can watch it happen: MUD 489 came down from $1.00 through 2015–2020 to $0.91, and MUD 249 fell from a $1.20 peak in the mid-2000s to $0.71.
The practical consequence is that on a $500,000 house, a $0.60 district and a $0.91 district differ by about $1,550 a year, every year — before you have bought anything different. Two houses five minutes apart. That is worth more attention than the countertops.
Send me a Cypress address
I will pull the MUD and what it levies, the flood designation on both the current and draft maps, and tell you whether what you are looking at on that foundation is clay or something worth worrying about.