Bailers vs. Pumps: Which is Better for Groundwater Sampling?

If you’re collecting groundwater samples, you’ve probably had to choose between using a bailer or a pump. Both have their pros and cons, and while pumps can work well in certain situations, bailers are often the smarter choice—they’re simpler, cheaper, and get the job done without the hassle of power sources or maintenance.

Let’s break down each method, when to use them, and why bailers usually come out on top.

What is a Bailer?

A bailer is about as simple as groundwater sampling gets—a long tube with a check valve at the bottom. You lower it into the well, water flows in, and when you pull it back up, the water stays inside. That’s it. No power, no moving parts, no complicated setup. Just a reliable way to grab a sample.

Types of Bailers

Bailers come in different materials and sizes depending on your needs:
• Polyethylene Bailers – Cheap, lightweight, and disposable, great for one-time use to prevent contamination.
• PVC Bailers – More durable than polyethylene but still affordable. These typically come in clear PVC or you can choose from white or clear with reusable options.
• Teflon® (FEP) Bailers – Chemically inert, perfect for collecting VOC samples without contamination.
• Weighted Bailers – Designed for deep wells or high-flow situations where you need the bailer to sink faster.

Why Bailers Are a Great Choice

✔ Cost-Effective – Much cheaper upfront compared to pumps, with no ongoing maintenance costs.
✔ No Power Required – Perfect for remote locations where electricity or batteries aren’t available.
✔ Portable & Lightweight – Easy to carry, transport, and use in the field.
✔ Reduces Cross-Contamination – Single-use options eliminate cleaning concerns, and reusable ones are easy to decontaminate.
✔ Easy to Use – No special training needed—just lower it, collect the sample, and retrieve it.

Challenges of Bailers

⚠ Only collects grab samples – If you need continuous sampling, a bailer won’t be the best choice.
⚠ Manual effort required – Lowering and pulling up a bailer over and over can be tiring, especially for purging.
⚠ Not Ideal for High-Volume Sampling – If you need a large amount of water quickly, using a bailer repeatedly can be time-consuming.

What is a Pump?

Pumps use mechanical or pneumatic force to pull groundwater up to the surface. Unlike bailers, which collect a single sample at a time, pumps can provide continuous sampling, making them useful for certain types of testing. However, they come with more moving parts, higher costs, and more maintenance.

Types of Pumps

• Peristaltic Pumps – Create suction by squeezing tubing, good for shallow wells but not great for VOCs.
• Bladder Pumps – Use compressed air to push water up without agitation, great for low-flow and VOC sampling.
• Submersible Pumps – Electrically powered and ideal for deep wells.
• Gas-Driven Pumps – Use compressed gas to lift water, often used for low-flow sampling.

Why Pumps Can Be Useful

✔ Continuous & low-flow sampling –Pumps can extract water gradually, preventing sample disturbance and reducing turbidity.
✔ Good for high-volume sampling – If you need to collect large amounts of water for multiple tests or lab analyses, a pump can be more efficient than repeatedly using a bailer.
✔ Can automate sampling – Good for long-term monitoring where you need frequent samples.

Challenges of Pumps

⚠ Expensive – Not just to buy, but also to maintain and repair.
⚠ Complicated setup – Requires tubing, a power source, and calibration.
⚠ Potential sample disturbance – Some pumps cause turbulence, which can alter test results.

So, Which One Should You Use?

It depends on your situation, but for most groundwater sampling needs, bailers are the clear winner. They’re easier, cheaper, and require almost no setup, making them perfect for routine sampling. While pumps have their place—especially for continuous low-flow sampling or deep wells—they introduce unnecessary complexity for most jobs.

If you want a hassle-free, reliable way to collect samples, stick with a bailer.