How Groundwater Becomes Polluted

A contaminated groundwater site with industrial pollution affecting the water supply.

Groundwater is one of our most valuable natural resources, supplying drinking water to millions of Texans and serving as a critical component of agriculture and industry. But what happens when this invisible water source becomes contaminated? More importantly, how can you tell if your groundwater is polluted, and what can be done to fix it?

At CRG Texas Environmental, we’ve spent over 30 years helping homeowners, businesses, and communities protect and restore their groundwater. In this article, we’ll break down how groundwater gets polluted, signs of contamination, and solutions for testing and cleanup.

What Is Groundwater and How it Becomes Polluted?

Groundwater is stored beneath the Earth’s surface in aquifers—layers of soil, sand, and rock that hold water. It moves slowly through these layers, naturally filtering out some impurities. However, this natural filtration is not foolproof, and pollutants can seep into the water supply.

Contamination happens when harmful substances from industrial waste, agriculture, landfills, and even households infiltrate the ground and mix with the water below. Once groundwater is polluted, it can take years—or even decades—to clean up, making prevention and early detection critical.

Common Causes of Groundwater Contamination

There are many ways groundwater can become polluted, but these are some of the most common culprits:

1. Industrial Pollution

Businesses that use and store chemicals, fuels, and heavy metals can contribute to groundwater pollution. Leaks from underground storage tanks, improper waste disposal, and accidental spills allow contaminants to seep into the soil.

Key Contaminants:

  • Petroleum products (oil, gasoline, diesel)
  • Solvents and degreasers
  • Heavy metals like lead, arsenic, and mercury

2. Agricultural Chemicals (Fertilizers & Pesticides)

Farmers rely on fertilizers, herbicides, and pesticides to grow crops, but these chemicals don’t always stay in the fields. They can leach into the ground, eventually reaching the water supply.

The biggest concern? Nitrate contamination. Nitrates from fertilizers are one of the most common groundwater pollutants and can be harmful, especially to infants.

3. Leaking Septic Systems & Sewage Issues

Many Texas homeowners rely on septic systems, but if they aren’t maintained properly, human waste can leak into the soil and contaminate nearby wells. Similarly, failing sewer lines can introduce bacteria, viruses, and harmful nitrates into the water supply.

Signs of groundwater contamination from septic leaks:

  • Unusual odors near your well or tap water
  • Discolored or cloudy water
  • Health symptoms (stomach issues, skin irritation) after drinking well water

4. Landfills & Hazardous Waste Disposal

Even when landfills are managed properly, toxic leachate (liquid waste) can escape and infiltrate groundwater. Illegal dumping of chemicals, paint, and motor oil further worsens the problem.

5. Natural Contaminants

Not all groundwater pollution is man-made. Some naturally occurring elements like arsenic, radon, and fluoride can dissolve into the water from the surrounding rock. While these contaminants aren’t the result of human activity, they can still pose serious health risks if present in high concentrations.

How to Tell If Your Groundwater Is Contaminated

If your home or business relies on a private well, it’s your responsibility to check for contamination—unlike city water supplies, which are regularly tested. But how do you know if your groundwater is polluted?

Here’s how to test groundwater for contamination:

  • Well Water Testing: A professional lab can check for bacteria, nitrates, heavy metals, and other contaminants.
  • Soil and Water Sampling: Environmental consultants (like CRG Texas Environmental) take samples to identify pollution sources.
  • Monitoring Wells: For large properties or businesses, installing a monitoring well allows for continuous groundwater testing.

Warning Signs of Contaminated Groundwater:

  • Water smells like gasoline, rotten eggs, or chemicals
  • Unexplained health issues (stomach problems, rashes, neurological symptoms)
  • Odd taste or discoloration in drinking water

How to Fix Groundwater Contamination (Remediation Options)

If your groundwater is polluted, what can be done? The right solution depends on the type and severity of contamination.

1. Pump-and-Treat Systems

One of the most common methods, this involves pumping groundwater to the surface, filtering out contaminants, and returning clean water to the aquifer.

2. Soil Vapor Extraction (SVE)

If volatile organic compounds (VOCs) like gasoline or industrial solvents are present, SVE technology can remove them by pulling vapors from the soil.

3. Bioremediation (Using Microbes to Clean Water)

Nature has a way of healing itself. Bioremediation involves using bacteria or fungi to break down pollutants naturally.

Real Example: A Texas Success Story
One of our clients in rural Texas had a diesel fuel leak from an underground storage tank that seeped into the groundwater. Instead of digging up massive amounts of soil, we used bioremediation techniques, allowing microbes to digest the hydrocarbons. Over time, the contamination levels dropped, and the water became safe again.

4. Permeable Reactive Barriers (PRBs)

For long-term cleanup, a PRB (a subsurface barrier made of natural materials) can trap contaminants before they reach drinking water supplies.

5. Excavation & Soil Replacement

For severe contamination, the only option may be to physically remove and replace the affected soil.

How to Prevent Groundwater Contamination

The best way to protect groundwater? Prevent contamination before it happens.

Homeowners Can:

  • Test well water annually
  • Dispose of chemicals properly (don’t dump them in your yard or drains)
  • Maintain septic systems to prevent leaks

Businesses Can:

  • Properly store fuels and hazardous chemicals
  • Monitor underground storage tanks for leaks
  • Invest in sustainable waste management practices

Texas Communities Can:

  • Support local water protection laws
  • Invest in groundwater monitoring programs
  • Encourage agricultural best practices to reduce chemical runoff

Final Thoughts: Take Action Now

Groundwater pollution is a serious issue, but early detection and remediation can save time, money, and environmental damage.

At CRG Texas Environmental, we specialize in:

If you suspect groundwater contamination or just want peace of mind, contact us today for a free consultation. Clean water starts with informed action!

📞 Call us at 713-474-1570| Serving all of Texas