Landfills operate under strict state and federal rules designed to protect groundwater, surface water and nearby communities. Meeting those requirements takes consistent sampling, precise reporting and a team that understands how monitoring programs work in the field and at the agency level.

This blog post answers common questions about how landfill monitoring works, why it's required and how our team can help your facility stay compliant. 

The basics

Landfill monitoring involves sampling regularly and preparing reports that give owners and agencies a clear picture of landfill health. No matter the type of landfill, all are designed to meet federal regulations and protect water sources from contamination. Most sites have groundwater wells around the perimeter that need routine testing to ensure contaminants like lead, chloride and Volatile Organic Compounds aren't present at levels that threaten environmental or human health.

Consistency is key. State-issued permits spell out what needs monitoring and how often to protect groundwater near the landfill. In Illinois, for example, the Illinois Environmental Protection Agency (EPA) issues Bureau of Land Operating Permits, National Pollutant Discharge Elimination System Permits and Water Pollution Control permits. Requirements often persist for decades after closure. Sites are usually monitored on a quarterly or semi-annual schedule, with sampling during the first two months of each quarter.

If organic or non-organic materials are found at higher than safe levels (called exceedances) based on their site-specific Applicable Groundwater Quality Standard (AGQS), confirmation sampling begins in the following quarter. Because these AGQS values are site-specific, a permit application must be submitted to an oversight organization like the Illinois EPA to determine if the landfill is the cause of the exceedance. Creating reports or proposing corrective plans in collaboration with agencies kickstarts the process for mitigating the exceedances.

Permits are issued before operations begin or if there is a change in operations or site conditions, or if the site is unable to satisfy the permit's reporting requirements. Fehr Graham helps clients navigate conversations with agencies like the Illinois EPA on everything from reporting to adjusting to permit changes. 

Landfill monitoring methods

​You might need all these tools and procedures or only a few, depending on your site.

Odor monitoring: Daily checks that help reduce impacts on nearby homes and businesses. A JEROME J605 hydrogen sulfide analyzer identifies odor concerns in locations in and around the landfill.

Gas monitoring: Monthly or quarterly checks using GEM5000 technology to measure methane, carbon dioxide, oxygen, nitrogen and pressure. It ends with reports for local agencies and permit applications if methane exceedances need to be addressed.

Groundwater sampling: Sampling falls into two categories, with both using a QED micro purge MP15 controller.

• Low-flow sampling: Often the primary method, using dedicated QED groundwater pumps or a QED bladder pump. Installing dedicated groundwater pumps when possible can reduce consumable costs and time in the field. Samples are collected after three consecutive field parameter readings within +/-10%.
• Bailing: Useful for wells with large water columns. Samples are collected after removing three well volumes. If a well runs dry, 24 hours should be enough time for it recharge and take another sample.

Stormwater sampling: Collected during or after rainfall to confirm runoff is not affecting the environment. These results are especially helpful when evaluating options such as full site closure.

Reporting: A critical part of compliance. Clear, thorough reports should identify groundwater or gas exceedances and outline next steps. Strong reporting can also save you money. If your landfill performs well, sample reduction applications and groundwater quality standard reviews can reduce sampling frequency.

Post-closure care: Even after closure, landfills require ongoing sampling and reporting to meet permit requirements, ensuring facilities stay compliant long-term. 

What to expect in the field

​Fieldwork is similar from one site to another, but it can occasionally bring surprises, especially with the weather. Sampling continues in most conditions, but good judgment is needed when conditions become unsafe or slow down the process. If equipment malfunctions, communication is key to adjust schedules to stay on track. Calibrating equipment before heading into the field and arranging rentals or replacements as needed also keep things moving.

Why we do it

​At Fehr Graham, we provide full-service landfill monitoring – from sampling to reporting – so clients get reliable data, stay compliant and often can reduce long-term costs. We're a one-stop shop for sampling and reporting, which is rare in our industry and often saves you money.

You may know us for our civil and environmental engineering work across Illinois, Iowa and Wisconsin. But we also support landfill owners and operators with comprehensive monitoring programs. Our environmental team regularly monitors landfills for the cities of Freeport and Jacksonville, Illinois, Waste Connections in Winnebago County, Illinois, Manitowoc Disposal & Recycling in Manitowoc, Wisconsin, and Sadoff Iron & Metal in Fond du Lac, Wisconsin.

Landfill monitoring may not grab headlines, but it plays a major role in protecting people and the environment. Consistent, long-term monitoring helps facilities stay compliant, avoid contamination and reduce costs over time as operations stabilize. Our team handles every part of the process so owners and operators have a reliable partner focused on compliance, clear communication and practical solutions.

If you need a simplified, cost-effective monitoring plan, our team can help.

Jake Piske is a Project Hydrogeologist who oversees environmental monitoring for landfills through fieldwork and reporting. He regularly samples landfills and conducts annual groundwater flow and impact assessments to ensure facilities comply with requirements. He also manages permit renewals and supports clients to maintain long-term environmental compliance. Reach him at This email address is being protected from spambots. You need JavaScript enabled to view it..