Do Maricopa septic systems need a Discharge Authorization?

It is the state's written permission to start using a septic system. Arizona's general permit rule, A.A.C. R18-9-A301, says that for a Type 4 General Permit (the category that covers septic systems), the person must receive "a written Discharge Authorization from the Director before the facility discharges." The rule also describes what the authorization does: it "allows a person to discharge under terms of the general permit and applicable requirements of this Article and the stated terms of the Construction Authorization."

The plain septic tank with a gravity-fed drain field is the 4.02 General Permit in R18-9-E302. It covers a septic tank with disposal by trench, bed, chamber technology or seepage pit, under 3,000 gallons per day of design flow. Other septic technologies, like mounds, drip systems and aerobic units, have their own permits, and the Discharge Authorization step applies to those too.

Maricopa County Environmental Services Department (MCESD) walks homeowners through the order in its septic guide. For new systems and alterations, there are three steps, and each one produces a document:

1. 1Application submitted. You receive an email or receipt from MCESD with your permit number, address and a reference to the septic work.
2. 2Application approved, construction permit issued. You receive a Construction Authorization Certificate for an Onsite Wastewater Treatment Facility.
3. 3System approved. You receive a Discharge Authorization Certificate or a "White Tag" stating "Authorization to Backfill" an onsite wastewater treatment facility.

The sequence matters. The state rule says "A person shall not begin facility construction until the Director issues a Construction Authorization."

You build the system, record any field changes, and ask for the authorization. The rule calls this the Request for Discharge Authorization. The Department "may inspect the facility before issuing a Discharge Authorization" to check that construction matches the approved design and that the general permit terms are met. If it finds problems, the Director must give you a written explanation of the deficiencies. Once construction and documents are satisfactory, the Director "shall issue a Discharge Authorization."

What you turn in depends on the system type (A.A.C. R18-9-A309):

• Gravity septic tank and drain field (R18-9-E302). The site plan has to accurately reflect "the final location and configuration of the components of the treatment and disposal works," and you or your agent certify on the form that the septic tank passed the watertightness test.
• Alternative systems (R18-9-E303 through E323). The package is bigger: as-built plans showing changes from the construction drawings, a final equipment and materials list, a final operation and maintenance manual, the installing contractor's name and Registrar of Contractors license number, a tank watertightness certification, and a Certificate of Completion from the engineer or designer of record. For some permit types it also includes a certification that a service contract exists for at least one year after the system starts operating.

The white tag is easy to misread. Its wording is "Authorization to Backfill," and the county lists it beside the Discharge Authorization Certificate as a step 3 document. Read which one you were handed before you connect the house.

The clock is two years. The rule says "A person shall complete construction within two years of receiving a Construction Authorization." If the Department hasn't received the final documents by the end of that period, "the Notice of Intent to Discharge expires, and the person shall not continue construction or discharge." You would then have to file a new Notice of Intent to Discharge and pay the fee again.

Septic approval tends to gate the rest of a project. The county's guide notes that "Many building jurisdictions will require MCESD septic review and/or approval prior to issuing building permit approval or Certificate of Occupancy." The county FAQ adds that Environmental Services "can only release building permits for unincorporated areas," so a home inside a city should ask that city's building department what it needs. Adding plumbing fixtures or bedrooms later can matter too: the guide says an increase in either "can increase the system demand and require system review by MCESD."

Hold on to the authorization. The rule requires a permittee under the Type 4 general permits to "maintain the Discharge Authorization and associated documents for the life of the facility." Those papers are useful when you sell. The state's transfer inspection and the septic inspection when buying a home in Arizona are a separate process, and a buyer will often ask to see the original approvals.

To check where an application stands, the county points to its Permit Center or the phone line (602) 506-6824.

• Get the Construction Authorization before anyone digs or sets a tank.
• Don't use the system until you hold the Discharge Authorization Certificate, and read your paperwork if all you were given is a white tag.
• Watch the two-year deadline from the day the Construction Authorization is issued.

Not sure whether your property is on septic at all? See how to tell if you have septic or city sewer in Phoenix. Planning the design? Do you need an engineer to design a septic system in Maricopa County covers who can draw the plans. For what the install can run, our septic system cost page explains what drives the price. The pipes inside the house are a different job, and HQ is licensed and insured, with free estimates and upfront pricing, for residential plumbing. This page is general information, not legal advice; confirm current requirements with Maricopa County Environmental Services.