State Septic Tank Regulations
State Septic Tank Regulations
Buying or replacing a septic tank is a state-by-state compliance exercise. OneSource's state guide index cites real statutes and state agencies, not internet lore.
How we write these guides. Every statute number, every setback distance, every tank-capacity table on a OneSource state page is sourced from the state's actual administrative code or regulatory agency publication. We cite the agency, the rule number, and the document URL. We never invent statute numbers, never paraphrase "standard industry practice" as if it were state law, and we update when rules change. If you find any state content that doesn't hold up to your local environmental health officer's scrutiny, email us and we will correct or retract within 24 hours.
Published State Guides
These guides are live with verified statutory citations.
Alabama
2-day detention rule, 1,000 gal min, +500 per spa, 100 ft to well / 5 ft property line
→ Read full guide
Alaska
Residential 1,000 gal + 250 gal/bedroom beyond 3; commercial 1.5×Q formulas; 100-ft setback to mean annual high water; permafrost and remote-bush engineering
→ Read full guide
Arizona
1,000/1,250/1,500 gal capacity; seepage pit option; 100% reserve area; Transfer Inspection pre-sale
→ Read full guide
Arkansas
<5,000 gpd subsurface / <2,000 gpd surface; 200-ft homeowner exemption; two-permit construction + operation model
→ Read full guide
California
1.2 million OWTS statewide; Tier 1-4 framework; 100/150/200 ft setbacks
→ Read full guide
Colorado
Table 9-1 capacity; 48-hour detention graywater provision; mountain frost engineering
→ Read full guide
Connecticut
1,000 gal min / 1,250 with disposal; 100 ft well / 200 ft public supply; DPH below 7,500 gpd, DEEP above; 2024 rule refresh
→ Read full guide
Delaware
Two-compartment + effluent filter REQUIRED; three-step professional process (Class D soil + Designer + Class E install); Inland Bays nitrogen attention
→ Read full guide
Florida
Multi-chamber tanks + outlet filter required; hurricane-zone anchoring
→ Read full guide
Georgia
Flat 1,000 gal for 1-4 bedrooms; +50% for garbage disposal; gray water bonus
→ Read full guide
Hawaii
Cesspool conversion mandatory by 2050 (priority 2030/2035/2050 per UH 2022 hazard tool); ~88,000 cesspools active; IWS limited to 2 dwelling units
→ Read full guide
Idaho
900/1,000 gal by BR; +250/extra; 2024-25 rule overhaul raised installer bonds + revised setbacks
→ Read full guide
Illinois
750 gal floor ≤500 gpd; 1.5×Q >500 gpd; 2+ tanks or multi-compartment >1,350 gpd; first comp 1/2-2/3 total; EPA UIC classification >1,500 gpd
→ Read full guide
Indiana
1,000–1,500 gal typical + 6.5 ft max water depth rule preventing tall-skinny tank capacity inflation
→ Read full guide
Iowa
1,250 gal OR 2× design flow floor; 150 gpd/BR; 40" min depth, 6.5 ft max capacity depth; 5 ft min length + 1.5:1 ratio
→ Read full guide
Kansas
1,000/1,200/1,500 gal by bedroom count; Table 5 setbacks; county Local Environmental Protection Program
→ Read full guide
Kentucky
1,000 gal (≤3 BR) → 1,500 gal (5 BR); +250 gal for garbage disposal
→ Read full guide
Louisiana
2.5 × design-flow capacity rule; 500 gal floor; 30–72" liquid depth; parish-level Sanitarian implementation
→ Read full guide
Maine
Licensed Site Evaluator (LSE) required; Sept 2023 amendments added watertight risers, 40-year-fill rule, seasonal-to-year-round conversion rules
→ Read full guide
Maryland
150 gpd/BR + 300 gpd floor; two-compartment required residential; commercial V=1.5Q or 1,125+0.75Q; BAT in Critical Area
→ Read full guide
Massachusetts
1,500 gal floor (notably high); 2023 Cape Cod nitrogen amendments; Title 5 inspection at property transfer
→ Read full guide
Michigan
Distinctive no-uniform-state-code model; 1.3M systems; Great Lakes watershed; pending statewide legislation
→ Read full guide
Minnesota
Table V tiers; ≥10 BR formula 2,500 + (BR-9)×250; garbage-disposal +50% capacity + multi-compartment
→ Read full guide
Mississippi
Regional environmentalist permitting; 50 ft setback baseline; Delta-to-coastal regional variation
→ Read full guide
Missouri
Dual-agency framework, county implementation, karst-zone engineering in Ozarks
→ Read full guide
Montana
4-ft natural soil to limiting layer (§17.36.320); §17.36.918 setbacks 10-100 ft; DEQ Eng Infra oversight
→ Read full guide
Nebraska
100 ft well/surface water setback; Table 2.1 distances; certified installer / REHS / PE designer flexibility
→ Read full guide
Nevada
Two-compartment required: inlet ≥2/3 capacity, 3×5 ft footprint, 30-72" liquid depth; §444.804
→ Read full guide
New Hampshire
75-ft setback radius up to 750 gpd; state-level NHDES design review; Oct 2025 rulemaking hearing (rules updating)
→ Read full guide
New Jersey
§7:9A-8.2 multi-compartment required for ejector pump / >1,000 gpd; seepage pit 150 ft to well; §7:9A-4.3 distances
→ Read full guide
New Mexico
Table 201.2 OR 2.5× design flow whichever greater; horizontal-line setback per Table 301.1
→ Read full guide
New York
5-day-retention sizing; Long Island I/A advanced treatment; NYC sewer-only
→ Read full guide
North Carolina
Tables XIV/XV capacity; 2-compartment or in-series required; grinder pump doubles capacity
→ Read full guide
North Dakota
SB 2267 centralized licensing/permitting with NDDEQ; Lake Agassiz clay challenges drainfields in Red River Valley; deep frost requires protected install
→ Read full guide
Ohio
1,000/1,500/2,000 gal capacity table; 2-compartment for 3+BR; NSF 46 effluent filter
→ Read full guide
Oklahoma
Individual + small public onsite systems; DEQ-certified installer framework (updated Nov 2025); tribal jurisdictions apply separately
→ Read full guide
Oregon
Simple 2-tier capacity (1,000 or 1,500 gal); county-agent permitting; coastal + volcanic soils
→ Read full guide
Pennsylvania
400 gpd baseline + 100 per extra BR; multi-compartment required; SEO-at-municipality permitting
→ Read full guide
Rhode Island
§6.23 setbacks (100/75 ft); §6.43 Salt Pond and Narrow River Critical Resource Areas denitrification mandatory; Class I-IV license framework
→ Read full guide
South Carolina
1,000 gal minimum, commercial peak-flow formula, 75/100 ft setbacks
→ Read full guide
South Dakota
1,000 gal floor ≤750 gpd + 250 gal/bedroom beyond 3; 50/75 ft tank-to-well (shallow penalty); 100/150 ft drainfield-to-well
→ Read full guide
Tennessee
Trench depth 24–48", 6-ft undisturbed earth between walls, Schedule 40 PVC piping
→ Read full guide
Texas
gpd-per-bedroom tank sizing; Class I/II installer licensing; aerobic ATU common
→ Read full guide
Utah
1.5× design flow with 1,000 gal floor; 300 gpd 1-2BR + 150/extra; unfinished basement = +1 BR
→ Read full guide
Vermont
Licensed Designer required; WW permit envelope <6,500 gpd; combined water-supply-plus-wastewater regulatory framework; Champlain phosphorus concerns
→ Read full guide
Virginia
Type I vs Type II framework, 12/24 soil depth rule, AOSS engineered alternatives
→ Read full guide
Washington
120 gpd/BR design flow; Puget Sound nitrogen-sensitive areas; 2024 rule rewrite
→ Read full guide
West Virginia
Table 64-47-K separations; Table 64-47-L sizing; steep-terrain + karst + coalfield regional variation
→ Read full guide
Wisconsin
Mandatory 3-year inspection cycle, 1/3-volume pumping trigger, licensed plumber with POWTS restriction
→ Read full guide
Wyoming
48-hr retention OR 1,000 gal floor (high-strength/non-res); Table 4 horizontal setbacks; §25-17 greywater allowed
→ Read full guide
States In Research Pipeline
We are building guides for every state. Each state guide is hand-researched against the governing state agency's actual administrative code, which takes time and is why we're not publishing placeholder pages. If you need immediate guidance for an un-published state, call us — we have the underlying research for most states already, we just haven't finished writing up the customer-facing guide.
Arizona
Research in progress
Colorado
Research in progress
Washington
Research in progress
Oregon
Research in progress
Pennsylvania
Research in progress
Ohio
Research in progress
Michigan
Research in progress
New York
Research in progress
Tennessee
Research in progress
South Carolina
Research in progress
Kentucky
Research in progress
Virginia
Research in progress
Alabama
Research in progress
Missouri
Research in progress
Indiana
Research in progress
Wisconsin
Research in progress
Minnesota
Research in progress
Iowa
Research in progress
Regulations change. Septic-system rules are amended by state agencies on a rolling basis. We monitor for changes in the states we have published but cannot guarantee real-time freshness. Before committing to a tank purchase, confirm the current rule with your county or state agency. If the rule has changed since our page was published, email us and we will update the guide.
Why State Rules Matter for Tank Selection
A polyethylene septic tank that ships compliant in Texas might 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 chambers, outlet filter, anchor straps, manway size, vent configuration) that vary.
When you order from OneSource, we verify your state's requirements against the specific tank configuration before shipment. This is not an automatic service offered by every tank reseller.
Getting Started
- Identify your state and county. Follow a state link above, or contact our team with your ZIP code.
- Call your local permit office. 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 state-specific configuration. Anchor straps, outlet filter, chamber count, manway size. Call us with the permit number and we'll ship the exact spec.