Hays County OSSF (Septic) Permit Guide: Steps, Documents and Tips

If you plan to build, replace or change a septic system in Hays County, you will need a permit. The state calls septic systems on-site sewage facilities, or OSSFs, and the county reviews and approves them before anyone breaks ground. This Hays County OSSF permit guide walks through the process in plain language, so you know what to expect and what to prepare.

A quick note on sources. This guide relies on information published by Hays County and the Texas Commission on Environmental Quality (TCEQ). Forms, fees and procedures change from time to time, so confirm the current details with the county before you file anything.

Who regulates septic systems in Hays County

Two layers of government are involved.

The state. TCEQ writes the statewide rules for on-site sewage facilities in 30 TAC Chapter 285. Those rules set design standards, setbacks, installer and designer licensing and maintenance requirements.

The county. TCEQ authorizes local governments to act as “authorized agents” and run the permit program. Hays County Development Services handles OSSF permits in the unincorporated parts of the county. The county’s authority comes from Texas Health and Safety Code Chapter 366 and its operating rules follow Chapter 285.

A few areas fall outside this program. Properties inside some city limits may be on city sewer or under other arrangements. If you are unsure whether your address is in the unincorporated county, ask Development Services before you hire anyone.

When you need a permit

Hays County requires a permit for:

• A newly constructed on-site sewage facility
• A replacement system
• Alterations or repairs that change an existing system

The county states that permits are required for unincorporated areas regardless of the size of the lot or acreage. That includes large ranch tracts.

Not every task counts as a permit-worthy change. Routine pumping or replacing a standard part is generally maintenance. Replacing tanks, changing the drain field or spray area, adding capacity or moving components does require review. When in doubt, call Development Services and describe the work. Our septic system repair page explains common repairs, and a licensed professional can usually tell you whether a permit is needed.

The people you will need

The process involves several licensed professionals and, sometimes, the owner.

Site evaluator or designer. A licensed professional evaluates the soil and site and prepares the design. They decide the system type and size based on the number of people, the strength of the wastewater and the soil, according to the county. In many cases the same person prepares the plans and the application package.

Installer. A licensed installer builds the system. Hays County allows a homeowner to install their own residential system, but only a licensed installer can install a system used for commercial purposes, which includes rental houses.

Maintenance provider. For aerobic and other advanced systems, a licensed maintenance provider holds the required contract. TCEQ no longer registers companies. It licenses individual maintenance providers.

You. The owner signs the application, pays the fees and keeps the records.

Documents you will typically need

Hays County lists the items it expects with an application. These generally include:

1. A completed OSSF application
2. A site plan and design prepared by a licensed professional
3. A location map
4. A floor plan of the home or building
5. A tax account summary or similar property information
6. For advanced or aerobic systems, a maintenance affidavit and a two-year initial maintenance contract
7. Application fees, per the county’s current fee schedule

Gather these early. Missing items are one of the most common reasons for delay. Ask your designer to give you a checklist before you start so nothing is overlooked.

The county will not issue a permit for a tract that violates its development or subdivision regulations. If you have a recently divided property, an older plat or a legal description with questions, sort that out first.

How to apply

Hays County uses an online portal called MyGovernmentOnline for permit applications. The county’s published information is not fully consistent about whether paper applications are accepted. One page suggests that the office does not take paper applications, and another says a paper form can be obtained in person. Call or visit Development Services to confirm how they want your application submitted today.

Most designers submit the application for you through the portal. Ask whether they will file it or whether you need to set up an account.

Review stages

After you apply, the process generally runs in two steps.

Administrative review. County staff check that the application is complete, the fees are paid and the paperwork is in order. The county says this can take several business days. If something is missing, they will ask for it.

Technical review. A county inspector reviews the design against state and county standards. They check setbacks from wells, property lines, structures and water features. They look at the soil evaluation, tank sizes, the layout of the disposal area and any special conditions. They may ask for revisions.

If the application passes, the county may issue an Authorization to Construct. This tells your installer they can begin work. The county later issues a Notice of Approval, which is the final permit documentation, after the system passes inspection.

Do not start digging before you have your authorization. Work done without it can be ordered torn out and redone.

Installation and inspections

Once you have authorization, the installer builds the system according to the approved plans. The county inspector must see key stages before the work is covered, which can include open tanks, the disposal area before backfill and, for aerobic systems, operating equipment. Your installer typically schedules these inspections.

If an inspector finds a problem, the installer must fix it before the work is covered. Changes to the plan usually need to be approved before they are built. Field conditions like unexpected rock can lead to design changes, which is common in the Hill Country where limestone and caliche lie close to the surface. Our post on septic systems in limestone and caliche soil explains why.

After final inspection and approval, keep your paperwork. You will want the permit, as-built drawings, the maintenance contract and any warranty information in one folder.

Aerobic systems and the maintenance contract

Aerobic systems carry an extra requirement in Hays County. The county states that all new on-site sewage systems requiring maintenance need an initial two-year contract with a licensed maintenance provider. You submit the signed affidavit and contract with your application. Homeowners may maintain their own system only after that initial period, according to the county.

State rules add that the provider must test the system and report to you and the permitting authority at least every four months, or every six months if the system has electronic monitoring. For more detail, see our guide to Texas aerobic septic maintenance contract rules. If you are choosing between system types, our comparison of aerobic vs conventional septic systems in Texas can help.

Fees, timing and budgeting

Fees depend on system type and are published in the county’s fee schedule. We do not list amounts here, because they change. Check the current schedule on the Development Services website or ask staff.

Total timeline depends on your design, the county’s workload and how quickly you respond to comments. Plan for weeks, not days, from start of design to final approval, and build in extra time for soil work, weather and rock. Do not schedule your move-in or a closing date until you have final approval in hand.

Total project costs include the designer, the application fees, the installer, any engineering and the maintenance contract. They vary a lot by site. For a general overview, see our septic system installation page.

Common mistakes to avoid

• Starting work before approval. Wait for the Authorization to Construct.
• Choosing the system before the soil evaluation. Let the site decide the design.
• Skipping the maintenance contract. An incomplete aerobic application will stall.
• Ignoring setbacks. Wells, creeks, slopes, easements and property lines all limit where components can go.
• Not planning for future needs. If you may add bedrooms, a guest house or a pool, tell your designer early.
• Hiring unlicensed help. Verify licenses for designers, installers and maintenance providers. Hays County publishes lists of OSSF designers, installers and maintenance providers on its documents page.
• Losing your records. Keep digital and paper copies.

Special areas and conditions

Parts of Hays County sit on or near the Edwards Aquifer recharge zone. State rules there require a minimum lot size of one acre per single-family dwelling using an on-site system and a 150-foot setback from recharge features. Other local rules may apply, and Hays County also has its own development regulations. Your designer should check each of them.

Flood-prone parcels along the Blanco River, Onion Creek and other waterways have extra setbacks and design considerations. Steep slopes limit where components can go. If any of these apply to your lot, raise them in your first conversation with the designer.

Selling or buying a property with a permit on file

If you are buying a home, ask the seller for the permit, approval and maintenance records, and ask the county what it has on file. Our guide to buying a home with septic in the Hill Country walks through the full checklist. Some permits and affidavits transfer with the property, so confirm what applies in your case.

Where to get help

The best place to ask a question about your specific permit is Hays County Development Services. The office lists a phone line at 512-393-2150 on its septic permit materials. Have your address and parcel information ready.

For help planning a system, we can talk through what the process looks like for your site and how it fits with your building plans. If you are in or near Dripping Springs or elsewhere in Hays County, request a free estimate and tell us about your property and project. We can also point you to the right next step if your question is about the permit itself.