Perc Testing & Septic System Design

BGI has become a prominent provider of conventional and alternative septic system designs, also known as on-site wastewater treatment systems, in Pima and surrounding counties.  Several hundred designs have been completed since 2003.  BGI has captured a large market share by providing services in a timely and cost-effective manner.

Process

The first step in the design process is to perform a septic site/soil evaluation in accordance with ASTM Standard D5921 (or in some instances a "perc" test).  This requires excavating of test pits and observations of site and soil conditions.  The evaluation will determine the type of septic system required as well as its necessary size and optimum location with consideration of site constraints.  An important decision at this point is to decide whether a conventional septic system will be adequate, or if too much rock in the soil or other factors necessitate the design of an alternative system. 

Conventional Septic Systems

In most cases, conventional system design is a relatively straightforward process.  BGI personnel will perform the field evaluation, then complete all necessary forms and site plans as required by the counties involved.  Typical costs (including excavating) are in the range of $750-$800.  If a letter is required for real estate transaction purposes, but a design is not needed, the total cost would be approximately $550-600.

Alternative Septic Systems

If a site is found to have too much rock in the soil, or has other constraints that disqualify its suitability for a conventional system according to State and/or local regulations, an alternative system design will be proposed.  The design and installation of an alternative septic system is more complex and time consuming, with more expensive materials as compared to a conventional system.

While some types of alternative systems are very costly, others are more reasonable.  BGI chooses to design only two of the most cost-effective systems.   One of the two following systems will be feasible to design and install on virtually any property that qualifies for septic system use:

Norweco Aerobic Treatment System

The Norweco Singulair aerobic treatment system is cost-effective and relatively simple.  Under gravity-feed conditions, the only moving part in the system is an aerator pump in the septic tank.  A pump tank with drip tubes may be added for especially challenging sites, such as those that have minimal soil cover or unfavorable topography.

In areas requiring nitrogen reduction, for example portions of Yuma County, a variation of the Norweco system (TNT) that simply includes a modification in the aeration schedule is a very cost-effective and uncomplicated solution for reducing nitrogen (nitrate) to acceptable levels, i.e. below the Arizona Department of Environmental Quality Aquifer Water Quality Standard of 10 mg/L.  A number of these systems have recently been successfully permitted and installed in Yuma County.  Please visit the Norweco link for more details and a downloadable brochure or see the the following local distributor's informative website. www.sonomexllc.com