Lagoon and Wastewater Pond Liner Requirements by State
Last verified September 1, 2026. Every row cites its rule.
This page is where to compare US state geomembrane liner requirements with links to the underlying regulations. It is a reference table of what each state's rules actually say about lining an animal-waste lagoon or an industrial or municipal wastewater pond. Every row links the rule or agency guidance it came from, and where the rule text carries no number, the table says so instead of filling the gap.
Most states do not regulate liner thickness. They regulate seepage (inches per day, or gallons per acre per day) or permeability (centimeters per second), and leave the liner design to the engineer. The mil numbers people quote, 60 mil HDPE most often, come from NRCS Conservation Practice Standard 521, which many states adopt by reference or by permit condition.
Treat the table as the starting point for a design conversation, not the end of it. The permit writer's requirement governs, and it can be stricter than anything printed here.
The two NRCS standards every state row points back to
NRCS CPS 313: Waste Storage Facility
December 2022
No numeric liner spec. CPS 313 sends liner design to CPS 520 (compacted soil), 521 (geomembrane or GCL), or 522 (concrete), and requires the foundation to meet the maximum specific discharge in AWMFH Appendix 10D or the state or local rule, whichever is more restrictive.
Read the standard (PDF)NRCS CPS 521: Pond Sealing or Lining, Geomembrane or Geosynthetic Clay Liner
August 2023
Table 1 sets minimum geomembrane thickness by material and by what the pond holds. This is the source of the 60 mil figure. The older 40 mil HDPE minimum for wastewater is superseded.
Read the standard (PDF)| Material | Wastewater | Clear water |
|---|---|---|
| HDPE | 60 | 30 |
| LLDPE | 60 | 30 |
| LLDPE-R (reinforced) | 45 | 24 |
| PVC | 40 | 30 |
| EPDM | 45 | 45 |
| FPP | 45 | 30 |
| FPP-R (reinforced) | 45 | 36 |
| GCL | 0.75 lb per sq ft | 0.75 lb per sq ft |
Liner requirements by state
Animal-waste rules first, industrial or municipal pond rules second. Where a cell says no number is stated, the rule text was read and carries none. Scroll sideways on a phone.
| State | Animal-waste rule | Stated requirement | Industrial or municipal pond rule | Notes |
|---|---|---|---|---|
| California | Title 27: retention ponds lined with, or underlain by, soils with at least 10 percent clay and not more than 10 percent gravel, or artificial materials of equivalent impermeability. No permeability number in the rule text. Central Valley dairies under Order R5-2013-0122 (adopted October 3, 2013): Tier 1 is a double liner of 60 mil HDPE or equivalent with a leachate collection and removal system between the liners; Tier 2 is NRCS California CPS 313 or equivalent, with a demonstration to the Regional Board. | None tabulated Not tabulated. Set by waste discharge requirements from the regional board with jurisdiction. | Other regional boards (North Coast, Lahontan) write their own pond conditions and are not tabulated here. | |
| Texas | Liner hydraulic conductivity no greater than 1 x 10-7 cm/s with a thickness of 1.5 ft or greater, and specific discharge through the liner no more than 1.1 x 10-6 cm/s calculated by Darcy's law. Geosynthetic liners are acceptable if they meet the specific discharge limit and are certified by a licensed Texas professional engineer. | Municipal wastewater pond liners: permeability no greater than 1 x 10-7 cm/s. TCEQ's guidance covers how to document in-situ and amended soils and how to request a variance under 217.203(c)(3). | One of the few states that puts a liner thickness in the animal-waste rule itself (1.5 ft of soil). The specific discharge test is what a geomembrane has to meet. | |
| Nevada | No CAFO-specific liner rule in NAC 445A (445A.435 and 445A.438 cover mining process ponds). NDEP guidance WTS-5 for treatment ponds: leakage no more than the equivalent of 12 in of material at 1 x 10-7 cm/s, or 500 gallons per day per acre; clay liner at least 12 in thick compacted to 90 percent Modified Proctor; geomembrane at least 60 mil with a permeability of 1 x 10-11 cm/s. Guidance, applied by permit condition. | WTS-5 as above for treatment ponds. WTS-37 for holding and detention basins: 60 mil primary and 40 mil secondary HDPE or equivalent, with a 500 gallons per acre per day action limit on the primary liner. Guidance, applied by permit condition. | Whether NDEP applies WTS-5 to CAFO lagoons is unconfirmed. Ask the permit writer before sizing a dairy or feedlot pond to it. | |
| North Carolina | 02T .1304 requires animal waste practices to meet NRCS standards. NC CPS 359: where a liner is required, a clay liner per AWMFH Appendix 10D, tested to a maximum hydraulic conductivity of 1.25 x 10-6 cm/s (0.003 ft per day). Membrane liners go through CPS 521. | Natural material liner at least 1 ft thick with a hydraulic conductivity no greater than 1 x 10-6 cm/s when compacted, or a synthetic liner with an effective hydraulic conductivity no greater than that. A pond floor less than 4 ft above bedrock needs a liner at 1 x 10-7 cm/s. | The 359 number (1.25 x 10-6) is a tested maximum on the built liner, not a design assumption. | |
| Iowa | Seepage through the seal no more than 1/16 in per day at the design depth. Compacted soil liner at least 12 in (24 in when suitable soil has to be imported), placed in lifts of 9 in or less at 95 percent Standard Proctor. A synthetic liner is allowed as an alternative; the rule states no thickness for it. | None tabulated Not tabulated. | Post-construction seal testing results go to the department in writing before start-up. | |
| Wisconsin | NR 243.15(3)(f) requires manure storage built after July 1, 2007 to meet NRCS Standard 313. WI CPS 313 in-place soil liner: at least 40 percent fines, plasticity index of 7 or more (12 or more above 600,000 cu ft of manure per year), at least 5 ft of total soil thickness with at least 1 ft recompacted, thickness calculated on a maximum permeability of 1 x 10-7 cm/s. Otherwise a liner per WI CPS 520, 521, or 522. | Soil liner design permeability no greater than 1 x 10-7 cm/s, compacted to at least 95 percent Standard Proctor. Synthetic liners at least 30 mil. Design loss from a lined lagoon no more than 500 gallons per acre per day. | The soil liner thickness is a calculated value; 5 ft and 1 ft are floors, not the answer. | |
| Minnesota | Non-concrete liners: maximum theoretical seepage of 1/56 in per day. Composite or aboveground: 1/560 in per day. A composite liner is a geomembrane, GCL, or comparable material over a constructed cohesive soil liner at least 2 ft thick; at least 3 ft of compacted cohesive soil under the synthetic for 1,000 animal units or more in sensitive groundwater settings. No cm/s value and no mil thickness in the rule text. | None tabulated Not tabulated. | MPCA's design handbook carries the detail behind the seepage numbers; it was not verified for this table. | |
| Georgia | AFO lagoons: seepage limited to 1/8 in per day (3.67 x 10-6 cm/s). Inside a significant groundwater recharge area: compacted clay or synthetic liner with a vertical hydraulic conductivity no greater than 5 x 10-7 cm/s. Swine operations over 3,000 animal units: synthetic liner required at 5 x 10-7 cm/s or better, and no single lagoon over 100 acre-feet. No thickness stated. | None tabulated Not tabulated. | The large-swine rule is the only row in this table that mandates a synthetic liner outright. |
States not yet tabulated: more are added as each rule is read against its source and verified. If you work with a rule we have wrong or missing, send it through the contact page and we will check it and update the row.
How to read a liner requirement
Seepage rate, permeability, and thickness are three different limits
A seepage rate (1/16 in per day in Iowa, 1/8 in per day in Georgia, 500 gallons per acre per day in Wisconsin and Nevada) limits how much liquid leaves the pond. It is a performance number. Any liner that hits it is acceptable, which is why these rules rarely name a material.
A permeability limit (1 x 10-7 cm/s in Texas and Wisconsin, 1 x 10-6 in North Carolina) describes the liner material itself. Combined with a thickness and a liquid depth, Darcy's law turns it into a seepage rate. Texas writes all three into one paragraph: 1 x 10-7 cm/s, 1.5 ft, and 1.1 x 10-6 cm/s specific discharge.
A thickness by itself (60 mil, 12 in of clay) is a construction spec. It only appears in the state rows where a state has adopted NRCS 521 or written a permit-condition guidance document like Nevada's WTS-5.
Why 60 mil HDPE shows up everywhere
NRCS CPS 521 Table 1 sets 60 mil as the wastewater minimum for HDPE and LLDPE, and 30 mil for clear water. Because CPS 313 routes every liner decision through 520, 521, or 522, any state that adopts NRCS standards inherits the 60 mil floor without printing it in its own rule. Nevada's WTS-5 and the Central Valley Tier 1 design land on the same number independently.
The reason is durability rather than permeability. A 30 mil sheet holds liquid as well as a 60 mil sheet; the extra thickness is for agitation, equipment traffic, gas uplift, and the freeboard band that sees sun and ice for decades.
Composite liners
A composite liner is a geomembrane or GCL laid directly on a compacted soil liner, so a hole in the sheet only leaks as fast as the soil underneath lets it. Minnesota defines it in rule (geomembrane or GCL over at least 2 ft of cohesive soil) and rewards it with a seepage allowance ten times tighter than a soil liner alone. Nevada's WTS-37 double liner with leak detection, and the Central Valley Tier 1 double HDPE with leachate collection, are the same idea carried one step further.
Frequently asked questions
Before you rely on this table
- This table is not legal advice. It summarizes rule text as read on the verification date and can miss context that the full rule, a permit, or a local ordinance supplies.
- Verify every requirement with the permitting agency before design. Regional boards, county health departments, and permit writers add conditions that never appear in the state rule.
- Rules change. Each row was checked against the cited source on the date shown at the top of the page; a later edition may supersede it.
Published September 1, 2026. Last verified September 1, 2026.
Lining a lagoon or wastewater pond?
We install geomembrane, GCL, and composite liner systems to the specification your permit calls for, with documented seam testing. If you are still working out which requirement applies, the agricultural liner post walks through how NRCS 521 sets thickness by what the pond holds.