State-mandated maintenance, aerobic vs. conventional, and what fails.

Septic systems treat and disperse household wastewater on-site. The two primary system types found in the Hill Country operate on fundamentally different principles — and the distinction has real operational and financial consequences for the owner.

The key operational difference: a conventional system, where it can be installed, is essentially passive. An aerobic system requires electricity, quarterly professional service, and ongoing consumables (chlorine tablets). If the power goes out, the aerator stops, and the system stops treating — it becomes a holding tank with a limited capacity before backup occurs.

Texas law requires aerobic septic systems to be inspected by a licensed maintenance provider. The standard requirement is quarterly inspections — every 3 to 4 months — with the provider checking aerator function, pump operation, control panel diagnostics, sludge accumulation, and spray field condition.

Annual maintenance costs range from $200 to $400 for the contract itself, plus the cost of chlorine tablets and any repairs. The maintenance provider submits inspection reports to the county; failure to maintain an active contract is a violation of state regulations and can result in enforcement action.

When buying a property with an aerobic system, ask for the current maintenance contract, the complete service history, and the name of the licensed provider. If the seller cannot produce these, assume the system has been neglected and budget for a full inspection and likely repairs before closing.

Aerobic septic systems have multiple mechanical and electrical components, each with a predictable service life. Knowing the failure points lets you budget for them — and recognize a neglected system before you buy.

• Aerator pump: The most common failure point. The aerator runs continuously and wears out. Replacement: $800–$1,500. Typical lifespan: 5–8 years. A failed aerator means the system stops treating — it becomes an anaerobic tank that will eventually back up.
• Spray heads: The sprinkler heads that distribute treated effluent across the spray field clog with mineral deposits or break from physical damage. Replacement: $75–$200 each. A broken spray head creates a wet spot in the yard and a potential health hazard.
• Control panel: Electrical components are vulnerable to power surges, lightning strikes, and moisture intrusion. Replacement: $500–$1,200. Symptoms include the alarm sounding continuously or the system not cycling.
• Drain field / spray field saturation: If the soil absorption area becomes saturated — due to system age, heavy rain, or hydraulic overload — the system backs up. This is the most expensive repair, often requiring a new drain field installation at $3,000–$8,000 or more depending on access and terrain.
• Chlorinator: The tablet feeder that disinfects effluent before spray distribution. If it runs dry or malfunctions, untreated water is being sprayed onto the property. Tablets cost approximately $50–$100 per year.

A properly maintained aerobic system should last 20–25 years before major component replacement. Systems that have been neglected — no maintenance contract, aerator not replaced on schedule, spray heads left broken — may fail in half that time. The maintenance history is your best diagnostic tool.