What changes if my site discharges to an impaired water?
For the portion of the site discharging to a water impaired for sediment or nutrients — or identified as Tier 2, 2.5 or 3, or within Lands of Exclusive Federal Jurisdiction — inspections move to once every seven calendar days and within 24 hours of a qualifying storm (Part 4.3.1).
It is the impairment parameter that matters
The trigger is impairment for sediment or nutrients, not impairment in general, plus the antidegradation tiers and the federal-jurisdiction case. Confirm what the water is actually listed for before deciding the clause applies — and re-check before construction starts, because listings change.
EPA publishes a mapping tool for this at https://www.epa.gov/npdes/epas-stormwater-discharge-mapping-tools.
Dewatering, if you do any
The same category of water pulls dewatering discharges into turbidity benchmark monitoring under Part 3.3, whose procedures then have to be written into the plan (Part 7.2.8).
Questions people ask
- Who decides whether the water is impaired?
- The listing is published by the state or EPA; the determination for your site is the operator's to make from that listing. SwpppDraft records your answer and prints the clause, it does not look the listing up for you.
- Does it affect the whole site or part of it?
- The clause applies to the portion of the site discharging to that water.
The states this question turns on
- Florida SWPPP requirements — Florida asks only that the SWPPP follow standard industry practices; it names no preparer qualification.
- Washington SWPPP requirements — Washington requires the permittee to prepare the SWPPP; the Certified Erosion and Sediment Control Lead requirement applies to site inspections.
- Virginia SWPPP requirements — Virginia requires only that SWPPPs be prepared in accordance with good engineering practices; its certification classes apply to agency reviewers and inspectors, not to preparers.
The documents this affects
Other questions
- Who can prepare a SWPPP?
- Which states require a licensed professional to prepare a SWPPP?
- Which states make you take a course before writing a SWPPP?
- Does my site need a licensed professional even though my state allows self-preparation?
- What acreage thresholds change SWPPP requirements?
Check your state and build a draft
The questionnaire and the generator run in your browser. Checkout is not open, so nothing can be charged.
Source: EPA 2022 Construction General Permit (as modified), Part 4.3.1, read 2026-08-04. County and city rules are not covered.
What we are, and what stays your responsibility
- SwpppDraft is a document generation tool. It does not provide engineering services, legal services, or compliance consulting, and no engineer or attorney reviews what it produces.
- Everything in the document is built from the site facts you enter. Checking that those facts are right, and that the resulting plan fits your project, is yours to do.
- We do not file anything on your behalf, we do not certify or endorse your compliance, and we accept no liability for what happens when you use the document.
- State-level requirements carry the date we verified them. County and city rules are not covered — some local jurisdictions require a licensed preparer even where the state does not, and you have to check that yourself.
- When the product opens, our total liability will be capped at the amount you paid us. Today that amount is zero, because nothing is for sale.