A conventional septic system (classified as Type 4.02 in Arizona) uses a septic tank and a gravity-fed drainfield to treat and dispose of wastewater. The drainfield may consist of chambers, rock trenches, EZ Flow bundles, or seepage pits. These systems are the simplest, most affordable, and lowest-maintenance option when soil percolation rates are adequate.
Type 4.02 Systems
Standard & Conventional Septic System Design
The most cost-effective solution for properties with good soil. Simple, durable, and low maintenance.
Conventional Septic Systems Designed for Arizona Soils
If your percolation test passes standard absorption rates, you qualify for a conventional gravity-fed septic system. We always aim to design these first because they typically cost significantly less to install and maintain compared to alternative systems. We don't over-design; we design what's right for your land and your wallet. Across Maricopa County and the Phoenix Metro, conventional systems remain the most common permitting path for properties with favorable soil.
Key Benefits
Lowest Install Cost
Conventional systems cost less to install than alternative systems when soil allows.
Longest Lifespan
Simple design means fewer components and proven long-term performance.
Minimal Maintenance
No pumps or advanced treatment to maintain; pump-out on a regular schedule.
Conventional Septic System FAQ
A properly designed and maintained conventional system can last 25 to 40 years or more. Longevity depends on soil conditions, usage patterns, and regular pump-outs. Because these systems have fewer mechanical components than alternative systems, there are fewer parts to fail over time.
Gravity-fed conventional systems require soil that absorbs water at acceptable percolation rates — typically measured during a perc test. The soil must not have excessive clay, bedrock, or caliche too close to the surface, and the water table must be deep enough. If your percolation test results fall outside acceptable ranges, an alternative system design may be required.
Fast Permitting for Standard 4.02 Systems.
Because these systems are standard, county review times are typically faster. We can often get your NOID (Notice of Intent to Discharge) approved in record time.
Start Your Design Need a Soil Test First?