Pinal County, AZ Environmental Rules: Erosion Control (2026)
Key Facts
- Trigger threshold
- 1 acre or more of land disturbance
- County approval
- Required before any disturbance begins
- Plan submission deadline
- 30 working days before construction
- Deficiency correction window
- 7 working days after notice
- Maximum civil penalty
- $2,500 per day, per violation
Summary
Unincorporated Pinal County requires a stormwater site plan and department approval before disturbing an acre or more of land. The plan must define best management practices that keep erosion in check and manage sediment transport throughout construction, per Code of Ordinances Section 20-66.
This pre-construction and construction phase stormwater site plan must consider possible water quality impacts and explain in sufficient detail the construction best management practices (BMPs) to be followed by the owner and all who work on the site. The site plan defines the BMPs to ensure that erosion will be minimized, sediment transport managed and that controls for other wastes are in place during the construction process.
Full Breakdown
Anyone disturbing an acre or more of land in the county's urbanized unincorporated area, or a smaller parcel that is part of a larger development plan, must get both an ADEQ construction permit (a notice of intent under the state's general permit) and a separate stormwater approval from the county's Community Development or Public Works department under Section 20-66. No disturbance is allowed until that county approval issues, and a copy of the approval plus the site's stormwater pollution prevention plan (SWPPP) must stay on site during all work hours.
The application requires a pre-construction and construction phase stormwater site plan submitted at least 30 working days before construction starts. That plan has to spell out the BMPs the owner and everyone working the site will follow so that erosion is minimized and sediment transport is managed, along with controls for other construction wastes; the department reviews the plan and returns comments or a letter of acceptance, and any revisions must be resubmitted before work begins. During construction the department can inspect the site under Section 20-70 to confirm the SWPPP is being followed and that BMPs are properly installed and maintained.
Section 20-67 exempts routine maintenance within an existing facility's original line, grade or capacity, sites with no reasonable probability stormwater will leave the property, sites qualifying for a low-risk erosivity waiver, sites already under an individual NPDES permit, emergency work, and land outside the urbanized unincorporated area defined in Section 20-9. Fees for review and enforcement are set by a separate board of supervisors resolution under Section 20-234.
Violations & Fines
If the SWPPP is not implemented or BMPs are not properly installed or maintained, the department notifies the owner or operator of the deficiency; failure to correct it within seven working days triggers a compliance order and referral to the county attorney under A.R.S. Section 49-261. The department may seek an injunction to halt work and civil penalties of up to $2,500.00 per day under Section 20-161, with each day of violation a separate offense; discharging stormwater without the required approval is also a criminal violation under Section 20-162.
Frequently Asked Questions
Do I need a county stormwater approval to build in unincorporated Pinal County?
What has to be in the stormwater site plan?
What happens if BMPs are not maintained on my construction site?
Sources & Official References
Other rules in Pinal County
Compare Pinal County to another location·View the Arizona environmental rules overview
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