State Septic Tank Regulations
All 50 States. Every Statute Cited to the Code.
The most thorough state-by-state septic and onsite-wastewater reference in the tank industry — all 50 states, every capacity table, setback distance, and statute cited to the state's own administrative code. No internet lore, no boilerplate. Find your state, confirm the exact tank configuration your code requires, and identify the agency that issues your permit.
The Federal Floor: What's the Same in Every State
There is no federal permit for a conventional residential septic system. Under the Clean Water Act, the EPA delegates onsite and decentralized wastewater regulation to the states, which in turn delegate day-to-day permitting to county health departments or licensed local agents. The EPA's role is guidance and the voluntary SepticSmart program — not approvals. A handful of federal rules still set a nationwide floor, and the tank-construction standards below apply no matter which state you build in.
Large-capacity systems & cesspools
Systems serving 20+ persons/day or receiving non-sanitary waste are Class V injection wells under the Underground Injection Control program (40 CFR 144–147). Large-capacity cesspools have been banned nationwide since April 2005.
Septage & biosolids
Land application and disposal of septage pumped from tanks is governed by 40 CFR Part 503 (Standards for the Use or Disposal of Sewage Sludge), implemented through the states.
Oil & chemical tanks (SPCC)
Aboveground oil storage at or above 1,320 gallons aggregate triggers a Spill Prevention, Control, and Countermeasure plan under 40 CFR Part 112 — relevant if you're also storing fuel or chemicals on site.
Tank construction standards
Prefabricated tanks are built to IAPMO PS 1 (prefabricated septic tanks), ASTM D1998 (rotomolded polyethylene), and CSA B66. Treatment and filter components follow NSF/ANSI 40, NSF/ANSI 245 (nitrogen reduction), and NSF/ANSI 46 (effluent filters).
Sources: EPA Septic Systems; EPA Underground Injection Control; 40 CFR Parts 112, 144–147, and 503 (eCFR).
All 50 State Guides
Every U.S. state is published with verified statutory citations, capacity and setback tables, the permitting agency, regional soil/climate considerations, and the tank configuration each code requires. Select your state.
How State Rules Differ — Patterns at a Glance
States diverge most on four things: minimum tank capacity, whether a two-compartment tank or effluent filter is mandatory, who administers the permit, and whether an inspection is required when a property changes hands. The summaries below are drawn from the cited rules on each state page — always treat the individual state guide as authoritative for your project.
Choosing & Sizing a Compliant Tank
Once you know your state's requirements, match them to the right tank and freight it to your ZIP. These tools and catalogs do the rest:
Why State Rules Matter for Tank Selection
A polyethylene septic tank that ships compliant in Texas can fail inspection in Florida, because Florida requires a multi-chamber configuration and outlet filter that Texas does not. A California Tier 1 installation may need anti-buoyancy anchoring that a Colorado install doesn't. The tank body is largely similar state to state — it's the specification details (number of compartments, outlet filter, anchor straps, manway size, vent configuration) that vary, and those details are exactly what an inspector checks.
When you order from OneSource, we verify your state's requirements against the specific tank configuration before shipment. That is not an automatic service offered by every tank reseller.
Getting Started
- Identify your state and county. Open your state guide above, or contact our team with your ZIP code.
- Call your local permit office. Nearly every state defers to county or local-agent administration for the actual permit. Confirm current fees, timelines, and any county-specific requirements.
- Get your site evaluation. A soils or perc test (depending on state) locks in your system design before you order the tank.
- Order the tank with the state-specific configuration. Anchor straps, outlet filter, compartment count, manway size. Call us with the permit number and we'll ship the exact spec, with freight quoted to your ZIP.
Methodology & Currency
Each state guide is researched directly against the governing state agency's administrative code and supporting handbooks, then spot-verified against the state legislature or rules portal. Where a rule was recently amended (for example, Colorado's 2025 Regulation 43 rewrite, Washington's WAC 246-272A revision, or North Dakota's 2025 SB 2267), the guide notes the change and cites the current version. We deliberately do not publish placeholder pages or generic "check with local authorities" filler.
This index and its 50 linked guides were last reviewed in May 2026. Regulations are amended on a rolling basis — confirm the current rule with your county or state agency before purchasing, and email us if anything here is out of date.
Frequently Asked Questions
- Does the EPA regulate my septic tank?
- Not directly. Under the Clean Water Act the EPA delegates onsite-wastewater regulation to the states, which delegate permitting to counties or licensed local agents. The EPA provides guidance and the voluntary SepticSmart program. The main federal exception is large-capacity systems serving 20+ people, which fall under the Underground Injection Control program (40 CFR 144–147).
- How big a septic tank do I need?
- Your state sets the minimum by bedroom count or design flow. Most states floor at 1,000 gallons (Illinois allows 750 for the smallest systems; Massachusetts requires 1,500). Use your state guide for the exact table, then our tank sizing calculator to confirm.
- Are plastic (polyethylene) septic tanks legal in every state?
- Most states accept polyethylene tanks that meet the recognized construction standard (typically IAPMO PS 1). A few maintain an approved-tanks list — Oregon's DEQ list is the clearest example — so confirm on your state page before ordering.
- Do I need a permit to replace an existing septic tank?
- Almost always, yes. Tank replacement is a permitted activity in nearly every state, handled by your county health department or a state-licensed local agent. Pulling and replacing a tank without a permit can block a future property sale.
- What is a "two-compartment" or "effluent filter" requirement?
- Several states (Delaware, Florida, Maryland, Nevada, North Carolina, Ohio, and Pennsylvania among them) require a two-compartment or multi-chamber tank and/or an outlet filter that screens solids before effluent reaches the drainfield. A single-compartment tank can fail inspection in those states.
- How often does a septic tank need to be inspected or pumped?
- It varies by state. Wisconsin mandates an inspection every three years; Massachusetts and Arizona require one at point of sale. As general guidance, conventional tanks are pumped every three to five years depending on household size and use.