| Bailer |
- The only practical limitations are size and materials
- No power source needed portable
- Inexpensive; it can be dedicated and hung in a well reducing the chances of cross-contamination
- Minimal outgassing of volatile organics while sample is in bailer
- Readily available
- Removes stagnant water first
- Rapid, simple method for removing small volumes of purge water
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- Time consuming, especially for large wells
- Transfer of sample may cause aeration
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| Submersible Pump |
- Portable; can be used on an unlimited number of wells
- Relatively high pumping rate (dependent on depth and size of pump)
- Generally very reliable; does not require priming
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- Potential for effects on analysis of trace organics
- Heavy and cumbersome, particularly in deeper wells
- Expensive
- Power source needed
- Susceptible to damage from silt or sediment
- Impractical in low yielding or shallow wells
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| Non-Gas Contact Bladder Pump |
- Maintains integrity of sample
- Easy to use
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- Difficult to clean although dedicated tubing and bladder may be used
- Only useful to approximately 100 feet in depth
- Supply of gas for operation (bottled gas and/or compressor) is difficult to obtain and is cumbersome
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| Suction Pump |
- Portable, inexpensive, and readily available
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- Only useful to approximately 25 feet or less in depth
- Vacuum can cause loss of dissolved gases and volatile organics
- Pump must be primed and vacuum is often difficult to maintain
- May cause pH modification
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| Inertia Pump |
- Portable, inexpensive, and readily available
- Rapid method for purging relatively shallow wells
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- Only useful to approximately 70 feet or less in depth
- May be time consuming to use
- Labor intensive
- WaTerra pump is only effective in 2-inch diameter wells
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