What are the requirements for installing a septic tank?
The tank should be installed on a six inch bed of pea gravel or sand to maintain stability. This is required when the tank is installed where jagged or large rocks are present. Access openings on the tank must be brought to within six inches of finished grade. If tanks are installed such that the top of the tank is greater than twelve inches below finished grade, MCESD-approved inspection risers (concrete or dual-wall corrugated polyethylene) are required. Tanks deeper than twenty-four inches are required to have a reinforced lid. The top of the tank shall not be greater than sixty inches below finished grade.

Native soil can be used to backfill the tank excavation as long as there are no jagged or large rocks in the mix that could damage the tank during or after backfilling. If jagged or large rocks are present, the soil must be screened to remove the potentially damaging rocks prior to backfilling.

The inlet t-baffle and in-line effluent filter at the outlet end of the tank must be easily accessible for maintenance and cleaning. Ensure that the inlet t-baffle can be easily reached and the effluent filter can be pulled up through the smaller inspection port on the top of the tank. If not properly aligned, the larger inspection plugs will need to be removed for routine maintenance.

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1. How do Onsite Wastewater Treatment Facilities (OSWTFs) work?
2. Why do Onsite Wastewater Treatment Facilities fail?
3. What items should not be put down the drain?
4. Do Onsite Wastewater Treatment Facilities (OSWTFs) cause health or water quality problems?
5. Can I apply for a permit to drill a well at the same time I apply for the Onsite Wastewater Treatment Facilities (OSWTF) permit?
6. My neighbor’s OSWTF is located on my property. What do I do?
7. What is an alternative system?
8. What are the different types of alternative systems allowed in Maricopa County?
9. Do I have to hire an engineer to design my system and draft my plans?
10. Can I make changes after I have submitted the NOID packet?
11. Can I make changes to an approved plan?
12. Can I request a partial construction inspection?
13. What type of rock should I use in the trenches, beds, or pits?
14. What are the requirements for installing a septic tank?
15. What are the requirements for installing the distribution box?
16. What are the requirements for installing the disposal field?
17. My system is failing. What do I do?
18. Can I use the existing septic system for my new house?
19. When can you release my building permit?