Denton County Septic Regulations: What Homeowners Need to Know in 2026

Denton County septic permits cost $310 for new installs and $100 for repairs through the Environmental Health Division. Aerobic systems require reports every 4 months.

Denton County is one of the fastest-growing counties in the entire country. A lot of that growth is pushing into areas that rely on septic systems, especially in the rural and suburban corridors around Aubrey, Ponder, Argyle, and the edges of Denton itself. If you live in unincorporated Denton County, the county's Environmental Health Division handles your septic permits. Properties inside the City of Denton go through the city's own Development Services Department instead.

As Nathan Glavy, a program specialist with the Texas A&M AgriLife Extension Service, has noted, "Inspecting and maintaining septic systems can help prevent negative impacts on local water quality and public health." That's especially relevant in a fast-growing county like Denton, where new construction on septic-dependent lots is booming.

This guide covers permits, fees, the application process, system types, lot requirements, aerobic rules, and enforcement in Denton County. Whether you're building on a new rural lot, maintaining an existing system, or buying a property with septic, the specifics are here.

Who Handles Septic Permits in Denton County?

The Environmental Health Division of Denton County Public Health is the authorized TCEQ agent for septic permits in unincorporated Denton County.

This division handles everything: plan review, permitting, inspections, maintenance verification, and enforcement for properties outside city limits. If your property is inside the City of Denton, the city handles your permit separately (and charges different fees). For properties in other municipalities within the county, check the TCEQ authorized agent list to confirm whether the city or the county is your permitting authority.

Denton County administers its septic program under TCEQ's 30 TAC Chapter 285 and Texas Health and Safety Code Chapters 341 and 366. The county emphasizes that property owners have complete responsibility for keeping their systems in "safe and sound working order."

Contact information:

Detail	Information
Office	Denton County Environmental Health Division
Phone	(940) 349-2920
Fax	(940) 349-2588
Website	dentoncounty.gov/Environmental-Health-Division
Address	3900 Morse Street, Denton, TX 76208

Applications are submitted in person at the Environmental Health Division office. The county does not currently accept septic permit applications through an online portal.

What Are the Septic Permit Types and Fees in Denton County?

New septic system permits in Denton County cost $310. Repair or modification permits cost $100. These fees are non-refundable regardless of permit outcome.

Here's what you'll pay for the most common permit types:

Permit Type	Fee	Notes
New OSSF installation	$310	All new residential systems
Repair or modification	$100	Any repair, extension, or alteration
Floodplain development permit	Varies	Required if property is in a floodplain
Culvert permit	Varies	Required if culverts are on or near property

These are county permit fees only. Your total cost includes the site evaluation by a licensed professional ($600-$1,200) and the installation itself. If you need a floodplain development permit or culvert permit from the Denton County Planning Department, those are separate fees on top of the OSSF permit.

Important rule on repairs: If you repair or upgrade 50% or more of your existing system, the county treats it as a new installation. You'll need a full new-system permit at the $310 fee.

The 10-acre exemption: Properties of 10 acres or larger with one single-family home, one septic system, and disposal components at least 100 feet from all property lines may qualify for a permit exemption. The exemption only covers the first system on the property. Even with the exemption, you still need a professional site evaluation and must meet all 30 TAC Chapter 285 technical standards. The exemption does not cover development permits or 911 addressing requirements.

How Does the Denton County Septic Permit Process Work?

The permit process requires an in-person application at the Environmental Health Division office. Permits can often be issued same-day if all documentation is complete.

Here's the step-by-step process:

1. Check your jurisdiction. Confirm that Denton County Environmental Health handles your permit. If you're inside City of Denton limits, the city handles it instead. For other municipalities, check the TCEQ authorized agent list.

2. Hire a licensed site evaluator. A Licensed Professional Engineer or Licensed Site Evaluator (with a Registered Sanitarian License) must evaluate your soil, conduct testing, and determine the right system type. This evaluation is mandatory before any system can be designed.

3. Gather documents. You'll need: the completed two-page permit application, site evaluation report, a to-scale site plan showing property dimensions, building locations, the proposed septic system layout, all wells within 150 feet, water lines, slopes, easements, floodplain areas, and distances to ponds, creeks, or swimming pools. For aerobic systems, include a signed maintenance contract. If your property is in a flood zone, include a flood elevation certificate.

4. Submit in person. Bring your complete application package to 3900 Morse Street, Denton, TX 76208. The application must be fully completed, and every field must be filled out. The county explicitly states the water well question must be answered or the application is void.

5. County review. The Environmental Health Division reviews your plans against 30 TAC Chapter 285. If everything is complete, permits can often be issued the same day.

6. Authorization to construct. Once approved, only a TCEQ-licensed installer can do the work.

7. Schedule final inspection. Contact the Environmental Health Division at least 2 days before you want the inspection. At inspection time, the septic tank must be in place but NOT backfilled, must be filled with water, drainfield must be complete, and the houseline must be connected.

8. Notice of approval. After the system passes final inspection, you receive a Notice of Approval. The system cannot be used until you have this document in hand. No dwelling may be occupied until the septic system passes.

How Does Denton County's Fast Growth Affect Septic Requirements?

Denton County's rapid growth means more rural subdivisions relying on septic systems. Minimum lot sizes for subdivisions with septic are one-half acre, and each property must pass a site evaluation.

Denton County's population reached 1,045,120 in 2024 and an estimated 1,068,355 in 2025, according to U.S. Census Bureau data and North Central Texas Council of Governments estimates. That's a 3.1% annual growth rate, adding roughly 31,600 new residents each year. Many of the new subdivisions appearing across the county's rural and suburban areas don't have access to municipal sewer, which means individual septic systems for every lot.

Subdivision requirements:

• Lots in subdivisions with public water and individual septic systems must be at least one-half acre (about 21,780 square feet)
• Lots with both a private water well and septic must also be at least one-half acre
• Properties subdivided before January 1, 1988 that don't meet current size minimums may petition for a variance
• Each lot in a new subdivision must pass an individual site evaluation before an OSSF permit will be issued

If you're buying a lot in a new Denton County subdivision that relies on septic, make sure the lot has passed its site evaluation and that you understand which system type the soil supports. Not every lot can handle a conventional system, and aerobic systems cost more to install and maintain.

What Are the Aerobic System Requirements in Denton County?

Aerobic systems in Denton County require a continuous maintenance contract with a licensed provider. Reports must be filed with the county every 4 months, and the contract must be renewed at least 30 days before expiration.

Many properties in Denton County end up with aerobic systems because the local soil conditions don't support conventional systems. If you have an aerobic unit, here's what the county expects:

Maintenance contracts are mandatory. You must have a current contract with a TCEQ-licensed maintenance provider at all times. No gaps in coverage are allowed. The initial maintenance contract covers 2 years from the date the system is approved.

30-day renewal deadline. Submit renewal documentation to the Environmental Health Division at least 30 days before your current contract expires. If your contract lapses without renewal, you must provide written evidence that you've completed approved homeowner training.

Reporting schedule: Your maintenance provider must inspect the system at least 3 times per year at approximately 4-month intervals. Reports go to both the county and to you. Systems with electronic monitoring may qualify for 6-month reporting intervals.

Homeowner self-maintenance option: Two years after initial installation, you may be able to maintain your own aerobic system if it uses secondary treatment, drip irrigation, or surface application disposal. But Denton County may have adopted stricter local rules. Contact the Environmental Health Division at (940) 349-2920 to confirm what's allowed for your system.

Chlorine requirements: Spray irrigation systems must have chlorine at all times. Use only calcium hypochlorite tablets certified for wastewater disinfection. Never use swimming pool chlorine tablets, which can create explosive gas and damage your equipment.

Maintenance affidavit: When an aerobic system is installed, you must file a notarized affidavit with the Denton County Clerk's Office. This gets recorded in the deed records and alerts future buyers.

After the initial 2-year contract, you can switch to any licensed maintenance provider.

What Happens If You Violate Septic Rules in Denton County?

Denton County investigates septic complaints within 30 days. Violations are misdemeanors with fines starting at $50, and repeat offenses can reach $1,000 with up to 6 months jail time.

The county's enforcement follows a structured process:

What triggers enforcement:

• Installing or modifying a system without a permit
• Failing to maintain an aerobic maintenance contract
• Systems causing odors, surface sewage, or contamination
• Damaged tank lids or improperly relocated spray heads
• Adding bedrooms without expanding the septic system
• Failing to maintain proper well setbacks after modifications

The enforcement process: When the county identifies a violation, you get a notice and typically have 30 days to make substantial progress on fixing the problem. If you don't act, the county can file a criminal complaint with the local justice of the peace court.

Criminal penalties: Under Texas Health and Safety Code Chapter 366, septic violations are misdemeanors. First offense fines range from $50 to $200. Repeat convictions carry fines of $200-$1,000, plus possible jail time of up to 6 months. TCEQ can pursue additional civil penalties up to $5,000 per day for serious violations.

Anonymous complaints: Anyone can file a septic complaint with the Environmental Health Division. Complaints can be filed anonymously, though the county can't report findings back without contact information.

How Much Does Septic Work Cost in Denton County?

A conventional septic system in Denton County runs $6,300-$7,500 for a 3-bedroom home. Aerobic spray systems cost $7,800-$9,800, and aerobic drip systems run $9,800-$12,000.

Here's what homeowners in the Denton, Aubrey, and Lewisville area should budget:

Item	Cost Range
Conventional system install (3-bedroom)	$6,300-$7,500
Aerobic spray system	$7,800-$9,800
Aerobic drip system	$9,800-$12,000
Site evaluation and soil testing	$600-$1,200
County permit fee (new system)	$310
Total permit + site eval	$910-$1,510
Septic pumping (1,000-gallon tank)	$235-$275
Aerobic maintenance contract (annual)	$300-$600
Typical repair (per hour + materials)	$275-$375/hour
Drain field replacement	$5,000-$12,000

Costs in Denton County track with the broader Dallas-Fort Worth metro area. The county's rapid growth has kept demand for septic installers high, so getting multiple quotes is a good idea. Many properties in the county have soil conditions that require aerobic systems, which adds $1,500-$4,500 to the installation cost compared to conventional.

For a full breakdown of Texas septic costs, see our septic pumping cost guide.

Frequently Asked Questions

Do I need a permit for septic work in Denton County?

Yes, for almost all work. New installations, repairs, extensions, and modifications all require a permit from the Environmental Health Division. The 10-acre exemption applies to the first system on large lots with proper setbacks, but even exempt systems must meet all TCEQ technical standards and require a professional site evaluation. Routine pumping does not require a permit.

How much does a septic permit cost in Denton County?

New system permits cost $310, and repair permits cost $100. Both are non-refundable. Budget another $600-$1,200 for the required site evaluation. If your property is in a floodplain, you'll also need a separate Floodplain Development Permit from the Planning Department. Total out-of-pocket for a new install permit package is typically $910-$1,510.

Who inspects septic systems in Denton County?

The Environmental Health Division handles all inspections. Contact them at (940) 349-2920 at least 2 days before you need an inspection. At the final inspection, the tank must be in place but not backfilled, filled with water, with the drainfield complete. For aerobic systems, your maintenance provider conducts inspections 3 times per year and files reports with the county every 4 months.

Can I do my own septic work in Denton County?

Installation and repairs must be done by a TCEQ-licensed installer. For conventional systems, homeowners can perform basic maintenance like monitoring and arranging for pumping. For aerobic systems, professional maintenance contracts are mandatory. You may qualify for homeowner self-maintenance after 2 years, but only with approved training and only for certain system types. Call the Environmental Health Division to confirm.

What's the minimum lot size for a septic system in Denton County?

For subdivisions, the minimum is one-half acre (about 21,780 square feet), whether the property has public water or a private well. Properties subdivided before January 1, 1988 that are smaller than current minimums may petition for a variance. Lot size alone doesn't guarantee you can install a system. The soil and site conditions must also support an OSSF, which is determined by the required site evaluation.

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Last updated: February 7, 2026 Reviewed by: Texas Septic Guide Editorial Team, content verified against TCEQ regulations, Denton County OSSF requirements, and 30 TAC Chapter 285

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Sources: Denton County Environmental Health Division, Denton County Public Health; Texas Commission on Environmental Quality (TCEQ), 30 TAC Chapter 285; Texas Health and Safety Code Chapter 366; Denton County OSSF Permit Application Packet; U.S. Census Bureau; NCTCOG 2025 Population Estimates; Texas A&M AgriLife Extension Service.

Serving Denton County communities: Denton | Aubrey | Lewisville