Phase I - Site and Soils Evaluation
A site/soils evaluation is a comprehensive investigation to determine the site suitability for the on-site wastewater
treatment facility (OSWTF). This is a two-part investigation: 1).Identify any limiting conditions which may affect the
size, type, and location of the OSWTF; 2). Evaluate the soils to establish a Soils Absorption Rate (SAR).
MCESD staff can conduct the site and soils evaluation for trench, chamber, or bed disposal. Arizona-registered engineers, geologists,
or sanitarians (with prior MCESD approval) may also conduct the evaluations or percolation tests. If the proposed disposal method is
a seepage pit, the site evaluation and seepage pit performance test must be conducted by an Arizona-registered engineer or geologist.
Site evaluations conducted by persons other than MCESD staff must be submitted on the
ADEQ Site Investigation Report form.
Instructions for Site and Soils Evaluation
- Three test holes (two in the primary disposal area, one in the reserve disposal area), excavated to a minimum depth of 12 feet, are required.
- Soil removed from each test hole is to be stockpiled in two separate piles, with material from the top half of each excavation placed closest
to the hole. A minimum of six stockpiles must be presented at the site.
- To request an inspection, call 602-506-1787. Please have your permit number available.
For a complete description of the different types of conventional disposal, Phase I application requirements and procedures, and an application
packet are required. Download the Phase I Site and Soils Evaluation Packet to obtain the information.