Pinal County Septic and Well Requirements for a New Home

There is usually no city sewer line and no city water main to tie into on rural Pinal County land, so you provide both yourself: a septic system for wastewater and a private well for water. These are two separate approvals from two different offices, and neither comes with the building permit. The county handles septic. The state handles wells. If you are building in or near Casa Grande or Apache Junction on a lot outside city utilities, this is the page for the water and wastewater half of your project. It explains what each approval requires, in what order, and how they tie together.

The septic side: a county permit ADEQ delegates

Wastewater on a rural lot goes to an onsite system, a septic system, permitted by the Pinal County Aquifer Protection Division, also called the Septic Program. The state owns the underlying rule. The Arizona Department of Environmental Quality (ADEQ) holds the authority for onsite wastewater permits and delegates it to each of Arizona's 15 counties, which then issue the permits on ADEQ's behalf. Pinal County describes the division's job directly:

Issue permits to construct septic systems (Conventional and Alternative). Inspect septic system construction. Review and endorse well permit applications for referral to the Arizona Department of Water Resources on parcels 5 acres and smaller.

In plain terms, the county runs the whole onsite-wastewater process. It permits and inspects both conventional systems (up to 24,000 gallons per day) and alternative systems (up to 3,000 gallons per day), the type used when ordinary soil conditions will not support a standard gravity leach field. Before a permit issues, your lot needs a site inspection by a qualified inspector, and the soil has to be tested for how fast it absorbs water. That absorption test is the perc test , short for percolation test, where water is timed draining from test holes in the proposed disposal area. The result sets the soil absorption rate, which decides the system type and size.

For example, say your five-acre parcel south of Casa Grande has tight, caliche-heavy soil that drains slowly. The perc test returns a slow rate. A conventional gravity leach field would then have to be very large, or the lot cannot fit one. The county may require an alternative system, which costs more to build and to maintain. This is why the soils work comes first. It can change your system type, your budget, and even where the house sits on the lot.

The well side: an ADWR Notice of Intent to Drill

Water on a rural lot usually comes from a private well, and the well is authorized by the Arizona Department of Water Resources (ADWR), the state agency, not the county. Before any drilling, you file paperwork with the state. The rule is the same statewide:

Prior to drilling a new well, or deepening or modifying an existing well, a person must file a Notice of Intent to Drill with the Department. Authority to deepen an existing well or drill a new well will be valid for one year. A licensed well-drilling contractor must perform the work.

A typical home well is an exempt well, which ADWR defines as a well pumping no more than 35 gallons per minute for domestic use. You file ADWR's Notice of Intent to Drill (form 55-40) with the filing fee. That registers the planned well and gives the licensed driller one year to complete it. Two catches matter for small lots. First, for an exempt domestic well on a parcel of 5 acres or fewer, ADWR requires a site plan showing the well is at least 100 feet from any septic tank or sewer, plus approval by the county health authority. Second, that county review is the step Pinal handles. The Aquifer Protection Division reviews and endorses the well application before it goes to ADWR on parcels 5 acres and smaller. So on a small lot, the county touches both your septic and your well.

When this comes into play

These two approvals govern any rural Pinal County build with no municipal utilities:

• Buying the land. Before you close on a lot, the perc result and the odds of a good well are part of whether the land is even buildable. A failed perc or a dry-hole risk can sink a deal, so this work belongs in your due diligence, not after.
• Designing the home. Your septic disposal area, your well, and your house all share the lot and have to keep required separation distances ( setbacks ) from each other and from property lines. ADWR's own 100-foot well-to-septic rule on small parcels is one of those distances, so the well and the leach field cannot crowd each other.
• Sequencing the build. The county septic permit and the ADWR well authorization run in parallel with your city or county building permit, and all three appear on the same site plan.

What this means for you

Treat septic and well as their own projects with their own timelines and budgets, separate from the house. Start the perc test early, ideally during due diligence before you buy, because a slow or failing result changes your system type and cost and can decide whether the lot works at all. File the Notice of Intent to Drill with ADWR and hire a licensed driller, and remember the authority is good for one year. If your parcel is 5 acres or smaller, expect the Pinal County Aquifer Protection Division to review the well application and confirm the 100-foot setback before ADWR signs off. Put the septic field, the well, and the house on one site plan so all the separation distances work together.

This entry covers the rural-utility half of the Pinal County builds. Because Casa Grande and Apache Junction are their own permit offices, the codes your home is built to are in Casa Grande Adopted Building Codes and Apache Junction Adopted Building Codes . The Maricopa-side equivalent of this page is Maricopa County Septic and Well Requirements , which covers a different county office. For the full picture, see the steps to building a custom home in Arizona and how to buy land to build a house in Arizona .

Source

The septic program and the small-parcel well review are published by the Pinal County Aquifer Protection Division: Wells & Septic on pinal.gov . The state delegation of onsite-wastewater permitting to the counties is published by ADEQ's Onsite Wastewater Treatment Program . The well requirements are published by the state at Well Drilling in Arizona .

This page is general information, not a substitute for the agencies' current rules. Septic permits, well filings, and fees change, so confirm the live requirements with the Pinal County Aquifer Protection Division and the Arizona Department of Water Resources before you rely on them.