Idaho septic system records

Septic systems in Idaho are governed by the Individual/Subsurface Sewage Disposal Rules (IDAPA 58.01.03) of the Idaho Department of Environmental Quality (DEQ). For permit records, DEQ sends you to the public health districts. DEQ says Idaho's seven public health districts administer the rules under a memorandum of understanding with DEQ. The districts conduct site evaluations, issue septic system permits, inspect installations, and assist with questions about existing systems and permit records.

In a Phase I ESA

ASTM E1527-21 does not name septic permit records among its standard record sources. They come up when a property is not served by a public sewer, and the questions are where the system is, what it was built to receive and whether it was permitted.

• Ask the health district, not DEQ. For questions about a specific property, septic permit or system, DEQ says to contact the public health district for the county where the property is located. Its Public Records Request page says the same: request septic permits, location and drawings through the health district.
• The district can speak to permit status and changes. DEQ lists what the districts can assist with, including permit status and existing permit records, and repairs, replacements, expansions and system modifications. Ask for the whole permit history, including any repair, replacement or expansion.
• Large systems also have a DEQ record. DEQ defines a large soil absorption system as a subsurface sewage disposal system designed to receive at least 2,500 gallons of wastewater per day, and says resorts, schools, subdivisions and rest areas not connected to centralized systems often use them. The design must be prepared by a professional engineer licensed in Idaho and undergo a plan and specification review by DEQ. An annual operation and maintenance report must be sent to both the health district and DEQ.
• Some systems need a groundwater evaluation. DEQ requires a nutrient-pathogen evaluation for proposed central septic systems located in nitrate priority areas or over sensitive resource aquifers, and for all proposed large soil absorption systems. That evaluation is a technical review of the system's potential impact on water quality. See groundwater quality and nitrate priority areas.
• Septage is defined by where it comes from. DEQ says domestic septage does not include material removed from septic tanks, holding tanks or similar treatment works that receive commercial or industrial waste, such as grease trap waste, commercial wastewater or industrial liquid. On a commercial or industrial property, ask what the system received.

DEQ's guidance to well owners says never to use a septic system to dispose of hazardous materials.

Where to ask

• DEQ's Septic and Septage page links the list of public health districts under the label Find Your Public Health District.
• The same page lists a DEQ staff contact for statewide onsite wastewater rules, technical guidance and matters that specifically require DEQ review. The DEQ State Office is at (208) 373-0502.

Getting the file

Permit records are requested from the public health district. The DEQ pages read do not say how each district takes requests. For DEQ's own records, such as a plan review for a large system, DEQ takes requests under the Idaho Public Records Act through its Public Records Request page.

Sources

Idaho Department of Environmental Quality pages, read October 1, 2026:

• Septic and Septage, last modified August 18, 2026.
• Wells, last modified November 24, 2025.
• Public Records Request, last modified August 18, 2026.
• Regional Offices, last modified August 6, 2026.