By Mark Faas, P2P Environmental
Groundwater is invisible. You can’t see it, smell it, or taste it—unless you look for it. And if you own or operate a commercial property, industrial facility, or property with history of chemical storage or use, understanding groundwater conditions should be on your radar.
Groundwater testing and sampling is one of the most important tools in environmental assessment and remediation. But it’s also one of the most misunderstood. Property owners often ask me questions like: “Do I really need groundwater sampling? Can’t we just test the soil?” or “What exactly are we testing for?”
Over my 25+ years in environmental consulting, I’ve helped dozens of Georgia and Southeast property owners understand groundwater conditions at their sites. Let me demystify groundwater sampling and explain what it tells you.
What Is Groundwater and Why Does It Matter?
Groundwater is water that exists below the soil surface, filling the spaces between soil particles and rock formations. In most areas of Georgia and the Southeast, groundwater exists at some depth—anywhere from 10 feet to less than one hundred feet below the surface depending on geology and location.
Groundwater matters for several reasons:
It’s a critical water resource. In many areas, groundwater supplies drinking water wells, irrigation systems, and industrial water supplies. Contaminated groundwater can affect entire communities.
Contamination spreads through groundwater. If soil at the surface is contaminated, contaminants can seep downward and enter groundwater. Once in groundwater, contaminants can spread horizontally with groundwater flow, potentially affecting properties far from the contamination source.
Groundwater is difficult to remediate once contaminated. While soil contamination can often be excavated and removed, groundwater remediation is typically long-term and expensive. Preventing groundwater contamination is far preferable to dealing with it after it occurs.
Property liability extends to groundwater. If your property’s contaminants migrate off-site through groundwater, you can be held liable for remediation costs both on your property and on neighboring properties.
When Groundwater Sampling Is Needed
Groundwater sampling typically occurs in two scenarios:
Scenario 1: Phase II Environmental Site Assessment
When Phase I ESA identifies a Recognized Environmental Condition (REC) suggesting possible soil or groundwater contamination, Phase II assessment often includes groundwater sampling. This is the most common scenario.
Typical Phase II groundwater work includes:
- Installing shallow monitoring wells on the property
- Sampling groundwater from these wells
- Analyzing samples for contaminants of concern based on property history (petroleum hydrocarbons if there’s fuel storage history, solvents if there’s manufacturing history, heavy metals for industrial operations, etc.)
- Determining if contamination has reached groundwater and, if so, the extent of contamination
Scenario 2: Compliance Monitoring or Remediation
If contamination has already been identified, groundwater sampling becomes part of ongoing monitoring or remediation:
- Monitoring to determine if contamination is spreading
- Baseline sampling before remediation begins
- Performance monitoring during active remediation
- Post-remediation sampling to verify cleanup
How Groundwater Sampling Works
Let me walk you through a typical groundwater sampling project:
Step 1: Site Assessment and Well Design
Before we sample, we need to understand site geology, groundwater flow direction, and where wells should be installed. This involves:
Geological review: We examine soil boring logs, geological maps, and site conditions to understand subsurface composition and groundwater depth.
Hydrogeological analysis: We determine groundwater flow direction (typically downgradient from higher elevation to lower elevation) and identify where monitoring wells should be placed to capture potential contamination.
Well location strategy: We typically install wells upgradient of suspected contamination source (background conditions), within or near the contamination source area, and downgradient (to detect if contamination is spreading).
Step 2: Monitoring Well Installation
Installing monitoring wells is straightforward but requires careful technique:
Drilling: We drill boreholes to the target depth using a drilling rig. Borehole depth depends on groundwater depth and contamination risk—typically 20-50 feet deep.
Well installation: A plastic or steel well casing (typically 2-4 inches in diameter) is installed in the borehole with a screened section at the bottom to allow groundwater entry.
Well development: The new well is “developed” by pumping water in and out to clear drilling mud and sediment. This ensures the well produces representative samples.
Documentation: We record borehole logs showing subsurface soil layers, depth to groundwater, and other geological information.
Step 3: Groundwater Sampling
Once wells are installed and developed, sampling proceeds:
Well purging: Before sampling, we remove water that’s been in the well casing (stagnant water) by pumping it out until fresh groundwater enters. This ensures we sample actual groundwater conditions.
Sample collection: We collect groundwater samples in appropriate containers (glass, plastic, or sterile depending on analytes). Samples are typically collected from multiple wells and at multiple depths.
Sample preservation: Samples are preserved with appropriate additives (preservatives, pH adjustment) to prevent degradation during transport to the lab.
Chain of custody: Detailed documentation tracks samples from collection through laboratory analysis. This is critical for regulatory compliance and legal defensibility.
Laboratory analysis: Samples are analyzed for contaminants of concern. Typical analyses include:
- Volatile Organic Compounds (VOCs) – for petroleum and solvent contamination
- Heavy metals – for industrial contamination
- Specific chemicals – for facility-specific contamination
Step 4: Data Interpretation
Once laboratory results come back, interpretation determines what the data means:
Comparison to standards: Results are compared to drinking water standards (Maximum Contaminant Levels, or MCLs) and soil/groundwater cleanup standards specific to Georgia and the property’s intended use.
Contamination delineation: We map where contamination exists, at what concentrations, and whether it’s contained to the source area or spreading.
Risk assessment: We evaluate whether contamination poses a risk for exposure (Is anyone drinking this groundwater? Could it migrate to a water supply?) and whether remediation is required.
What Contamination Looks Like in Groundwater
Groundwater contamination varies depending on historical property use:
Petroleum sites (gas stations, fuel depots, auto repair): Typical contaminants: Benzene, toluene, xylenes, total petroleum hydrocarbons Concentration range: Parts per billion (ppb) to parts per million (ppm) Risk: Volatile compounds can accumulate in buildings; contamination can spread with groundwater
Dry cleaning or solvent-using facilities: Typical contaminants: Perchloroethylene (PCE), trichloroethylene (TCE), other chlorinated solvents Concentration range: Usually ppb to ppm Risk: Highly toxic; small concentrations can exceed drinking water standards; remediation is complex
Industrial sites with heavy metals: Typical contaminants: Lead, chromium, arsenic, zinc, cadmium Concentration range: Highly variable depending on operations Risk: Bioaccumulative; drinking water exposure is most significant concern
Manufacturing with multiple contaminants: Typical: Mixture of petroleum, solvents, metals Risk: Complex and difficult to remediate
Typical Groundwater Sampling Costs and Timeline
Understanding what groundwater work costs helps you budget:
Phase II with groundwater component:
- Well installation (3-5 wells): $5,000-$10,000
- Groundwater sampling and analysis: $2,000-$6,000
- Geological evaluation and report: $1,500-$3,000
- Total: $8,500-$19,000 (typically $10,000-$15,000)
Timeline: 4-6 weeks from initial site assessment to final report
Remediation monitoring (if contamination is found):
- Semi-annual groundwater sampling (ongoing): $3,000-$7,000 per event
- Annual report preparation: $3,000-$9,000 per event
- Duration: Typically 2-10 years depending on remediation approach
Costs are variable based on property size, well depth, number of wells, number of contaminants analyzed, and site accessibility.
Do I Really Need Groundwater Sampling?
Here’s how to determine if groundwater sampling should be part of your environmental assessment:
You definitely need groundwater sampling if:
- Phase I identified historical petroleum storage or fuel operations
- There’s history of hazardous chemical use or storage
- Soil contamination has been found on the property
- Your property is upgradient of water supply wells or sensitive groundwater resources
- Property groundwater is or could be used for any purpose
- Regulatory agencies have indicated concern about your property’s groundwater
Groundwater sampling is recommended if:
- Phase I identified potential sources of contamination and groundwater is shallow
- The property is in an area with fractured bedrock (groundwater can travel quickly)
- Neighboring properties show evidence of contamination
- Phase I specifically recommends groundwater assessment
Groundwater sampling may not be needed if:
- Phase I found no evidence of contamination sources
- Property use is low-risk (office, retail, residential)
- Groundwater is very deep (100+ feet) and unlikely to be affected
- Property sits in an area with naturally poor groundwater quality
Working with Environmental Professionals on Groundwater Projects
If you need groundwater assessment, partner with qualified professionals:
Credentials to verify:
- Hydrogeological expertise (hydrogeologist or environmental scientist)
- Experience with groundwater in your specific area and geology type
- Familiarity with Georgia regulatory requirements
- Experience with remediation (not just assessment)
- Reference from other property owners or lenders
Questions to ask:
- Why do you recommend groundwater sampling for my property?
- What specifically are you sampling for?
- How many wells will you install and where?
- What’s the timeline?
- What will results tell us?
- What’s the total cost and what does it include?
At P2P Environmental, we approach groundwater assessment conservatively: We recommend it when necessary and explain why it’s needed. Many properties benefit from Phase II soil assessment alone; others genuinely need groundwater evaluation. We help you understand which applies to your property and develop a cost-effective assessment strategy.
The Bottom Line
Groundwater sampling answers critical questions about your property’s environmental condition:
- Is contamination present in groundwater?
- Is contamination migrating off-site?
- What’s the extent and severity?
- What remediation, if any, is needed?
For property owners, lenders, and developers, documented groundwater assessment is powerful protection. It gives you factual data about site conditions, informs business decisions, and provides legal documentation of your due diligence.
Don’t let groundwater remain a mystery. If your property has contamination potential, understanding groundwater conditions is essential risk management.
Contact P2P Environmental
Phone: 678-565-4435
Website: p2penvironmental.com/contact
Whether you’re assessing a property you own, financing, or planning to develop, we’re here to guide you through groundwater assessment and interpretation. We serve property owners, lenders, and developers throughout Georgia and the Southeast with practical, cost-effective groundwater solutions.