What Will My Monthly Payment Be on a Katy New Build?
A $450,000 new construction home in Katy, TX costs approximately $4,316 per month in September 2026, not the $3,427 a generic mortgage calculator shows. Mohebbi Realty Group builds every estimate from seven components: principal, interest, base property tax, MUD tax, homeowners insurance, HOA dues, and private mortgage insurance.
TL;DR
A $450,000 new build in a Katy, TX MUD community runs about $4,316 per month in September 2026 with 10% down at 6.75%, roughly $889 more per month than a generic online calculator estimates.
MUD taxes in Katy, Cypress, Fulshear and Richmond master-planned communities typically run $0.25 to $1.00 per $100 of assessed value, adding $94 to $375 per month on a $450,000 home.
Combined property tax rates in new Katy and Fulshear master-planned communities generally fall between 2.75% and 3.50%, versus the 1.1% national default most calculators assume.
Houston is the most expensive major metro in Texas for homeowners insurance, with an average premium of $5,653 in 2025 per Insurify, though new construction in Katy typically quotes lower at $2,800 to $4,500 per year.
If a lender escrows on the builder's lot-only tax value, the payment can jump more than $1,500 per month in year two once the finished home is assessed.
The Freddie Mac 30-year fixed rate averaged 6.71% as of September 3, 2026.
Key Takeaways
Ask your lender one question before you sign: "Is my escrow set on the lot value or the estimated finished value?" The answer determines whether you face a year-two payment shock.
Pull the MUD rate for the specific address, not the community. Two lots 400 feet apart can sit in different districts with a 0.50% rate difference — about $188 per month on a $450,000 home.
Budget the one-time HOA capital contribution separately. It is due at closing, is not part of the monthly payment, and typically runs $400 to $2,500.
Why is the payment on a mortgage calculator wrong for Houston?
Generic mortgage calculators are wrong in Houston because they apply a national default property tax rate near 1.1% and omit MUD taxes and HOA dues entirely. A Katy new build in a MUD district can carry a combined rate near 3.00%, almost triple the default.
The error compounds three ways:
Tax rate too low. A 1.1% default on $450,000 is $413 per month. The real figure in a Katy MUD community is closer to $1,125 per month.
MUD tax missing. Most listing-portal estimators have no field for a special utility district.
HOA and PMI omitted or guessed. Master-planned community dues and private mortgage insurance are frequently left at zero.
Insurance underestimated. National averages near $1,900 per year do not reflect Gulf Coast wind and hail exposure.
The result is a payment estimate that looks affordable and is not. On our worked example below, the gap is $889 per month — roughly $10,668 per year of budget that does not exist.
How much does a MUD tax add?
A MUD tax adds $94 to $375 per month on a $450,000 home in the Houston suburbs, depending on the district's rate. MUD rates in the Katy and Cypress area generally run from $0.25 to $1.00 per $100 of assessed value, with newer districts at the high end.
A Municipal Utility District is a special-purpose taxing entity that issues bonds to fund water, sewer, drainage and sometimes roads and parks in subdivisions built outside city utility service. Homeowners repay those bonds through a tax that sits on top of school, county and other rates.
The $281 monthly spread between a $0.25 district and a $1.00 district is worth roughly $43,000 of loan amount at 6.75%. Two identical homes at identical prices are not the same purchase. Under Texas Water Code Section 49.452, a seller conveying property inside a district must deliver written notice of the district's tax rate and bonded indebtedness before a binding contract is executed. Read it.
How much is homeowners insurance in the Houston suburbs?
Homeowners insurance on a new construction home in Katy typically costs $2,800 to $4,500 per year, or $233 to $375 per month. Houston is the most expensive major metro in Texas for home insurance, with an average premium of $5,653 in 2025 according to Insurify data reported by the Houston Chronicle.
New construction quotes below the metro average for three specific reasons: the roof is zero years old, the home is built to current wind-load code, and there is no claims history on the property. Roof age is the single largest rating factor in the Texas market in 2026.
Two cost drivers buyers routinely miss:
Wind and hail deductibles in the Houston market are often a percentage of dwelling coverage — 1% or 2% — not a flat dollar amount. On $400,000 of dwelling coverage, a 2% deductible is $8,000 out of pocket.
Dwelling coverage is replacement cost, not purchase price. Insuring a $450,000 home for $450,000 usually overpays for the land and can still leave a coinsurance gap if construction costs rise.
What do HOA dues and capital contributions add?
HOA dues in Katy-area master-planned communities typically add $100 to $150 per month, and a one-time capital contribution of $400 to $2,500 is due at closing. The dues are recurring and escrowed by some lenders. The capital contribution is not part of the monthly payment.
A capital contribution — also called a capitalization fee, working capital fee or foundation fee — is a one-time, non-refundable payment to the association's reserve fund, charged at every transfer of title. It is commonly quoted as a flat amount or as a fraction of the sale price. Expect a transfer fee and a resale certificate fee of $250 to $500 on top of it. Ask for the association's fee schedule in writing during the option period. First-time homebuyers are the group most often caught by this at the closing table.
What does a $450,000 home in Katy actually cost per month?
A $450,000 new build in a Katy MUD community costs approximately $4,316 per month with 10% down, a 6.75% 30-year fixed rate, and a 3.00% combined tax rate. The Freddie Mac survey average was 6.71% as of September 3, 2026.
A generic calculator using a 1.8% tax rate, $1,500 insurance, and no MUD, HOA or PMI returns $3,427. The difference is $889 per month.
These are illustrative figures at a 3.00% blended rate. The actual rate is set per address by the specific overlapping jurisdictions, and it varies across the Katy service area by more than half a percentage point.
How does that compare in Cypress, Fulshear and Richmond?
The same $450,000 home costs $4,216 to $4,358 per month across Katy, Cypress, Fulshear and Richmond, a spread of $142 driven almost entirely by tax rate and HOA dues. That $142 monthly spread equals roughly $22,000 of purchasing power at 6.75%.
A buyer holding a firm monthly ceiling can afford a materially more expensive house in Fulshear than in Richmond, or a materially better lot in Cypress than the sticker price suggests. Rates inside a single city vary too: mature districts in Katy where bonds are largely retired sit well below newly opened sections a few miles west in Fulshear and Richmond.
Why does the payment jump in year two?
The payment jumps in year two because Texas appraisal districts value property as of January 1, so a home still under construction on that date is taxed on the lot alone. When the finished home is assessed the following January, the escrow account is short and the servicer collects both the higher ongoing tax and the accumulated shortage.
Here is the same $450,000 Katy home under two escrow setups:
Escrowed on finished valueEscrowed on lot value onlyYear 1 monthly$4,316$3,428Year 2 monthly$4,216$4,980Change−$100+$1,552Year 3 monthly$4,216$4,216
Both homes settle at the same number. Only one of them ambushes the household budget with a $1,552 monthly increase in year two. The year-two figures assume the school district homestead exemption of $140,000 has been filed, which cuts roughly $123 per month off the school tax portion.
Two more year-two details:
File Form 50-114 with your appraisal district. The exemption is not automatic, it is free, and it also caps annual taxable value increases at 10% — but the cap does not apply until the year after the exemption is first granted.
Insurance renews at year one too. Texas premiums rose in consecutive years through 2026, so plan for a renewal increase alongside the tax adjustment.
How do I check the real number for a specific address?
Verify a specific address in four steps, all free and all completable in about fifteen minutes.
Identify the county and pull the tax record. Katy spans Harris, Fort Bend and Waller counties. Search the address at hcad.org, fbcad.org or the Waller County Appraisal District to see every overlapping jurisdiction and its adopted rate. Sum them.
Request the MUD notice. Ask the builder for the Texas Water Code Section 49.452 notice showing the district's current rate and outstanding bond debt. Districts adopt rates between September and December, so a notice delivered in September 2026 may still reflect the prior year's rate — ask whether a change is on the table.
Get a bindable insurance quote, not an estimate. Provide the exact address, year built, roof material and square footage. Confirm the wind and hail deductible structure.
Ask the lender the escrow question in writing. "Is my escrow set on the lot value or the estimated finished value, and what is the payment once the home is fully assessed?" Get the second number.
Which Houston communities does this apply to?
This applies to nearly every master-planned community in the western and southwestern Houston suburbs, because MUD financing is how infrastructure gets built outside city utility service. Specific examples across our service area:
Elyson in Katy — 2026 annual assessment of $1,464, newer MUD, Katy ISD.
Cane Island in Katy — Waller County portion, different county rate structure than Harris County Katy.
Cinco Ranch and Firethorne — more mature districts, lower MUD component.
Bridgeland and Towne Lake in Cypress — Harris County, combined rates in the 2.9% to 3.2% band.
Cross Creek Ranch in Fulshear — section-by-section HOA variation from $1,400 to $3,000.
Harvest Green, Aliana and Candela in Richmond — Fort Bend County, LID and MUD overlays vary by section.
Why Mohebbi Realty Group
We hold relationships with 40+ builders across all price points in Greater Houston, which means we see the escrow setup on new construction contracts before the buyer does. Bobby Mohebbi is an Accredited Buyer Representative (ABR), a Pricing Strategy Advisor (PSA), and ranks in the top 1.5% of agents nationwide per RealTrends. We run the seven-component number on the specific address, not the community average, and we ask the lender the escrow question in writing on every new build. Mohebbi Realty Group works throughout Katy, TX and Greater Houston.
Frequently Asked Questions
How much does a MUD tax add to a monthly payment in Katy, TX? A MUD tax adds approximately $94 to $375 per month on a $450,000 home in Katy, TX, depending on the district's adopted rate. Rates generally run from $0.25 to $1.00 per $100 of assessed value. Newer districts with unretired infrastructure bonds sit at the high end of that range.
Does the mortgage calculator on Zillow or Redfin include MUD taxes? Generic online mortgage calculators do not include MUD taxes. They apply a default property tax percentage, frequently near 1.1%, and typically have no input field for a Municipal Utility District or HOA dues. In a Katy new construction community, this understates the true monthly payment by several hundred dollars.
Why did my mortgage payment go up after the first year on my new build? Texas appraisal districts value property as of January 1, so a home still under construction on that date is taxed on the lot value alone. When the completed home is assessed the following January, the escrow account is short. The servicer raises the payment to cover both the higher ongoing tax and the accumulated shortage, which can exceed $1,500 per month for twelve months.
Is homeowners insurance cheaper on a new construction home in Katy? Yes. New construction in Katy typically quotes $2,800 to $4,500 per year, below the Houston metro average of $5,653 reported by Insurify for 2025. The savings come from a zero-year-old roof, current wind-load construction standards, and no prior claims history on the property.
What is an HOA capital contribution in a Katy master-planned community? A capital contribution is a one-time, non-refundable payment to the homeowners association's reserve fund, collected at closing every time the property changes hands. In Katy and Fulshear communities it commonly runs $400 to $2,500, separate from annual dues and separate from transfer and resale certificate fees of $250 to $500.
Get the real number for your address
Call or text (832) 455-3565 and we will pull the tax record, the MUD rate and a bindable insurance quote for any specific address in Katy, Cypress, Fulshear or Richmond — before you sign a builder contract.
Touring new construction? Request our current builder tour list at mohebbirealtygroup.com/new-construction — 40+ builder relationships across Greater Houston, at no cost to you as a buyer.
Bobby Mohebbi | Mohebbi Realty Group | Keller Williams Signature 920 S Fry Rd, Katy, TX 77450 | (832) 455-3565 | Bobby@mohebbirealtygroup.com
Accredited Buyer Representative (ABR) · Pricing Strategy Advisor (PSA) · Veterans Affairs Certified Agent (VACA) · Short Sales & Foreclosure Resource (SFR) · Top 1.5% of agents nationwide per RealTrends · Keller Williams Signature Top Producer · Agent Leadership Council