--- title: "How Long Does PFAS Stay in Soil? Years, Decades, Longer" description: "PFAS do not break down in the environment. See what long-term soil studies show, what changes how fast PFAS move, and what to do if your soil may be affected." url: https://www.aes-stl.com/blog/how-long-does-pfas-stay-in-soil publisher: Advanced Environmental Services phone: +1-314-865-2662 quote: https://www.aes-stl.com/contact --- PFAS: 6 min read, published August 31, 2026 # How Long Does PFAS Stay in Soil? Years, Decades, Longer No source gives one number for every site. PFAS carbon-fluorine bonds do not break down in the environment, so time alone rarely clears a site. In one 5-year lysimeter study of silty soil with some clay and natural rainfall, 96.88% of PFOA and 99.98% of PFOS stayed in the soil. [Request a Quote](https://www.aes-stl.com/contact)[(314) 865-2662](tel:+1-314-865-2662) ![Aircraft hangar with a yellow fire truck and equipment during an AES PFAS project](https://www.aes-stl.com/_astro/pfas-2025-06-24-11.09.00.CKLsY786_1Qvvzs.webp) ![Red fire suppression tanks and piping in an aircraft hangar during an AES PFAS project](https://www.aes-stl.com/_astro/pfas-2025-06-24-10.58.33.C9OzVSit_Z1cGw0W.webp) ![Large warehouse floor with AES equipment in the distance](https://www.aes-stl.com/_astro/pfas-warehouse-2025-12-03-11.52.27.BVKPsHAu_sbKVc.webp) No one can tell you a single number of years. What the sources do say is clear: PFAS do not break down in soil the way most pollutants do. The Minnesota Pollution Control Agency states that the carbon-fluorine bonds that define PFAS “do not break down in the environment.” Plan for a problem that lasts decades, and test before you assume it has faded. This post explains what long-term studies show, what makes PFAS stay or move, and what a Missouri property owner should do first. For the basics, see our glossary entries on [PFAS](https://www.aes-stl.com/glossary/pfas) and [forever chemicals](https://www.aes-stl.com/glossary/forever-chemicals). ## Do PFAS break down in soil? Not in a way that clears a site. PFAS can change into other PFAS, but the bond that gives them their staying power stays intact. The Minnesota Pollution Control Agency writes: “PFAS may transform to other PFAS, but the carbon-fluorine bonds characteristic of PFAS do not break down in the environment.” EPA scientists say the same thing in plainer words: because of the strong chemical bonds, PFAS “are difficult to destroy.” That is why the nickname “forever chemicals” fits. AES’s own PFAS page says PFAS resist natural degradation and persist in soil and water for decades. ## What does a long-term soil study show? It shows that most of the mass stays put. ITRC’s PFAS guidance reports on a long-term lysimeter study. A lysimeter is a soil column that lets researchers collect the water that passes through. The soil was silty with some clay, and the rain was natural. ITRC writes that “even after 5 years, 96.88% and 99.98% of the mass of PFOA and PFOS, respectively, remained in the soil.” Read the conditions before you reuse that number. It is one study, one soil type and one set of weather. It does not give a half-life for your yard. It does show that five years of rain did not flush out nearly all of two well-known PFAS. See the glossary for [PFOA](https://www.aes-stl.com/glossary/pfoa) and [PFOS](https://www.aes-stl.com/glossary/pfos). The same study found that PFOA and shorter-chain PFAS traveled faster through the soil column than PFOS. So different PFAS behave differently at the same site. ## What makes PFAS stay in soil or move to groundwater? Water, soil makeup and the type of PFAS decide it. ITRC says the leaching potential “will be enhanced in areas with high water infiltration rates, which may include natural water sources such as precipitation or human-made sources such as irrigation.” Depth to the water table matters too. PFAS-specific effects can slow leaching, such as sticking to soil particles. Factor What ITRC says it does Heavy rain, flooding or irrigation Promotes downward leaching of PFAS in unsaturated soil Deep water table (thick unsaturated zone) Affects leaching potential Soil with more organic carbon, surface area or surface charge Can limit leaching, because PFAS stick to the soil Longer-chain PFAS Less soluble, larger partitioning coefficients than shorter-chain PFAS Shorter-chain PFAS and PFOA Moved faster than PFOS in the lysimeter study The table has a practical meaning. Soil that holds PFAS can act as a slow source. ITRC warns that “slow leaching of PFAS from shallow soils may contribute to a persistent groundwater plume.” Because the levels of concern in water are measured in parts per trillion, even a small steady release matters. Our glossary explains [parts per trillion](https://www.aes-stl.com/glossary/parts-per-trillion-ppt). EPA describes the same path: PFAS can seep through the soil and migrate into groundwater, and the compounds can stick in the unsaturated zone and release slowly. ## How long until PFAS in soil reach groundwater? Possibly 1 or 2 years, possibly several decades or longer. ITRC says: “Time scales required for PFOS (and other PFAS that exhibit strong interfacial adsorption characteristics) to reach the underlying groundwater have been simulated to be from 1 or 2 years to several decades or longer.” Read the condition: these are computer simulations, not a measurement at your site. Climate and PFOS concentration change the answer. Use the range to set expectations, not to predict one lot. Question What the sources support Will the soil clear on its own? No source supports that. The carbon-fluorine bonds do not break down in the environment How long can PFAS stay in the ground? Decades or longer is the planning assumption. One 5-year study kept 96.88% of PFOA and 99.98% of PFOS in the soil How fast can PFAS reach groundwater? Simulations range from 1 or 2 years to several decades or longer, by site Does rain help? It can move PFAS down. It does not remove them from the site Does the soil also matter if my water is clean right now? Yes. Slow leaching from shallow soil can feed a groundwater plume later ## Where do PFAS in soil come from? From places where PFAS products were made, used or burned. AES’s PFAS pages list firefighting foams, coatings and manufacturing processes as common uses. ITRC adds that releases often involve surface applications and air deposition, so soil can pick up PFAS near a source and at some distance from it. Think about your property’s history. Was there a fire training area, an industrial plant, a plating shop, a landfill or a fire station nearby? Those questions guide where to sample. Our PFAS pages cover [PFAS contamination](https://www.aes-stl.com/pfas-contamination) and the facilities AES serves. ## Does Missouri track PFAS in soil? Not that we found for private lots. Missouri DNR says that since 2013 it has run PFAS occurrence monitoring “for public drinking water supplies through federal and voluntary sampling programs.” Its PFAS Viewer maps voluntary sampling in public water systems. That is useful if you are on city water. It tells you little about the soil on your own land. If you own a former industrial site, a farm with biosolids history or land near a foam release, assume you need your own data. Do not rely on a nearby map point. ## What should you do if your soil may have PFAS? Work in order. Do not dig, haul or sell soil before you know what is in it. 1. **Write down the site history.** Note past uses, fires, spills and neighbors with industrial history. 2. **Sample soil and groundwater.** A plan should say where, how deep and how many samples. Our [PFAS sampling](https://www.aes-stl.com/pfas-sampling) and [PFAS testing](https://www.aes-stl.com/pfas-testing) pages explain the process. The guide on [PFAS testing for property owners](https://www.aes-stl.com/guides/pfas-testing-for-property-owners) walks through it. 3. **Read the results with a professional.** Units, detection limits and compound names matter, and a result in parts per trillion is not the same as one in parts per million. 4. **Check water too.** If a well is near the soil, test the well. See [PFAS drinking water](https://www.aes-stl.com/pfas-drinking-water). 5. **Compare cleanup options only after you have data.** See [PFAS soil treatment](https://www.aes-stl.com/pfas-soil-treatment) and [soil remediation](https://www.aes-stl.com/glossary/soil-remediation). If the soil is also headed off site, talk about disposal rules early. Our page on [PFAS waste disposal](https://www.aes-stl.com/pfas-waste-disposal) is a starting point. If your question is about the water side, read our post on [whether PFAS can be removed from drinking water](https://www.aes-stl.com/blog/can-pfas-be-removed-from-drinking-water). ## Can you wait it out? Waiting does not fix a source that is still releasing PFAS. It can also let a groundwater plume grow. If your soil tests above a level that matters for your use, a lender, a buyer or a regulator, you need a plan, not a calendar. Waiting may be reasonable for one case: a low result on a good sample, with no well nearby and no change planned for the land. Even then, keep the lab report and re-sample if the use of the land changes. ## Next step If you need PFAS soil testing or cleanup on a Missouri or Midwest site, start with our [PFAS service page](https://www.aes-stl.com/pfas) and call AES at (314) 865-2662, or send the details through [/contact](https://www.aes-stl.com/contact). AES quotes each job. ## Frequently asked questions ### Do PFAS ever break down in soil? Not in a way you can count on. The Minnesota Pollution Control Agency says PFAS may transform into other PFAS, but the carbon-fluorine bonds that define PFAS do not break down in the environment. A different PFAS can appear in the soil without the contamination going away. ### Will rain wash PFAS out of my soil? Some PFAS leach downward with rain, flooding or irrigation, but not all at the same speed. ITRC reports that PFOA and shorter-chain PFAS moved faster through one soil column than PFOS. Slow leaching from soil can also feed a long-lasting groundwater problem, so soil and water both matter. ### Can I tell if my soil has PFAS by looking at it? No. PFAS have no color or smell you can use as a test, and the amounts that matter are tiny, measured in parts per trillion. Only a lab test of a soil sample can show which PFAS are present and how much. Use a sampling plan, not a guess. ### Does Missouri test private property soil for PFAS? Missouri DNR describes PFAS monitoring of public drinking water supplies, not soil on private lots. Its PFAS Viewer maps voluntary sampling in public water systems. If you think your land is affected, you need your own soil and groundwater sampling by a qualified team. ### How do you remove PFAS from soil? EPA says the strong chemical bonds make PFAS difficult to destroy, so cleanup usually means a site plan built on test results. The right method depends on the PFAS present, the soil and the groundwater. Start with sampling, then compare options with a remediation company. ## Terms on this page - [Parts per trillion (ppt)](https://www.aes-stl.com/glossary/parts-per-trillion-ppt) - [Forever chemicals](https://www.aes-stl.com/glossary/forever-chemicals) - [Soil remediation](https://www.aes-stl.com/glossary/soil-remediation) - [PFAS](https://www.aes-stl.com/glossary/pfas) - [PFOA](https://www.aes-stl.com/glossary/pfoa) - [PFOS](https://www.aes-stl.com/glossary/pfos) ## Sources 1. [Minnesota Pollution Control Agency: PFAS ambient background concentrations](https://www.pca.state.mn.us/sites/default/files/tdr-g1-25.pdf) 2. [ITRC: PFAS Environmental Fate and Transport Processes, 5-year soil study](https://pfas-1.itrcweb.org/5-environmental-fate-and-transport-processes/) 3. [ITRC: PFAS Environmental Fate and Transport Processes, groundwater plume](https://pfas-1.itrcweb.org/5-environmental-fate-and-transport-processes/) 4. [ITRC: PFAS Environmental Fate and Transport Processes, leaching factors](https://pfas-1.itrcweb.org/5-environmental-fate-and-transport-processes/) 5. [ITRC: PFAS Environmental Fate and Transport Processes, travel time to groundwater](https://pfas-1.itrcweb.org/5-environmental-fate-and-transport-processes/) 6. [U.S. EPA: Addressing Challenges of PFAS, protecting groundwater](https://www.epa.gov/sciencematters/addressing-challenges-pfas-protecting-groundwater-and-treating-contaminated-sources) 7. [Missouri DNR: Per- and Polyfluoroalkyl Substances (PFAS)](https://dnr.mo.gov/contaminant-spotlight/perfluoroalkyl-polyfluoroalkyl-substances-pfas) Written by Advanced Environmental Services and checked against the sources above on August 31, 2026. Rules change, so check the linked page before you act. ## Keep reading - [PFAS testing for property owners: when to test, how sampling works and what results meanTest for PFAS if your property sits near an airport, military base, landfill or industrial site, used firefighting foam, or draws from a private well. A site assessment picks sample points, trained staff collect clean samples, and an accredited lab reports results in parts per trillion. AES says most results arrive in two to four weeks.](https://www.aes-stl.com/guides/pfas-testing-for-property-owners) - [Can PFAS Be Removed From Drinking Water? What WorksYes. EPA names granular activated carbon, anion exchange, reverse osmosis and nanofiltration as the best available technologies for meeting its PFAS limits. EPA says a home filter could also be an effective way to reduce PFAS, if it is certified for PFAS and maintained. A filter may not help if your water has no PFAS.](https://www.aes-stl.com/blog/can-pfas-be-removed-from-drinking-water) - [Mold remediation cost and timeline: what AES publishes and what drives the priceAES says prices typically range between $1500 to $10,000 for a home showing visible signs of mold, and 1 to 5 days is the normal timeframe for most average jobs. Severity, affected materials and the size of the contaminated area move both numbers. AES quotes each job after an evaluation.](https://www.aes-stl.com/guides/mold-remediation-cost-and-timeline) - [How Long Does It Take to Demolish a House? A Missouri TimelineAES says that if all the paperwork is present, a house can often be demolished in as little as 3 to 5 days. AES also says a small to medium building takes 5 to 10 days without extra work such as asbestos removal. Permits and notices can take a minimum of 10 working days first.](https://www.aes-stl.com/blog/how-long-does-it-take-to-demolish-a-house) - [Asbestos in older St. Louis homes: where it hides and what to doAsbestos can hide in floor tile, floor adhesive, siding, roof shingles, textured walls, pipe wrap, furnace parts and attic insulation. About 87% of St. Louis city housing units and 68% of St. Louis County units were built before 1980. The only way to know is a lab test from a certified inspector.](https://www.aes-stl.com/guides/asbestos-in-older-st-louis-homes) - [What drives asbestos removal costAsbestos removal cost depends mainly on how much material there is, where it sits, how hard it is to reach, and what testing, notice fees and disposal the job needs. Angi's 2026 national average is $2,260. AES publishes no asbestos prices and quotes each job after a survey.](https://www.aes-stl.com/guides/asbestos-removal-cost) ## Request your custom environmental remediation estimate Contact us for a free environmental remediation or restoration estimate and a personalized solution to your problems. [Or call (314) 865-2662](tel:+1-314-865-2662)