Introduction to Water Sampling Pump Systems

An overview of how a water sampling pump system is assembled and operated. You can purchase a complete Waterra water sampling pump system here at EQUIPCO. A basic system consists of a foot valve and appropriate sized tubing. We also carry pumping actuators, surge blocks, and other accessories.

Basic Inertial Pump Operation

All Waterra foot valves can be used for conventional sampling, and are operated in the same manner. The pump consists of a foot valve attached to a length of tubing. To operate this pump:

  • Tubing/Valve assembly is installed in well. Water level inside tubing rises to that in well.
  • A rapid upstroke closes the foot valve and lifts the water column inside the tubing a distance equal to the stroke.
  • At the end of the upstroke, the water column continues to rise due to its momentum. A further column of water is thus simultaneously drawn into the tube.
  • Pushing the tubing down immediately after the upstroke forces a further column of water into the tubing due to the inertia of the water column.
  • The cycle is repeated and water rises in pulses to discharge at the surface.


Waterra inertial pump systems are frequently used as an efficient and cost effective way to purge wells. Both standard flow and high flow foot valves work great for purging.

The process of purging is the same as conventional sampling, just removing a lot more water. To assist with the pumping action we recommend a pumping mechanism for purging applications


Both the standard flow and high flow foot valves are used in surging applications. We recommend the standard flow for 2 inch wells up to 130 feet, and the high flow for 4 inch wells and deeper 2 inch wells. The operation is the same as purging, we carry surge blocks to help increase the surging action. Pumping mechanisms are also recommended for this application.

Well Development

Waterra inertial pumps are recognized as one of the best development tools for 2 inch monitoring wells and some 4 inch wells. Both the standard and high flow foot valves can be used depending upon well diameter and depth. The pump operates in the same manner as purging or surging. We recommend a surge block and pumping mechanism to increase efficiency.

Drive Point Sampling

Waterra's micro flow foot valves can sample wells with an opening as small as 0.5 inches. If a larger foot valve can be used it should, but sometimes the micro flow is the only foot valve that will fit. These pumping systems are usually hand operated but if assistance is required the electric hydrolift II can be used.

Collapsed, Damaged, or Obstructed Wells

The low flow foot valve with it's 0.5 inch OD, and the even smaller micro flow foot valve with a 0.375 inch OD can push past obstructions where no other pumping system can fit. The largest foot valve that will fit should be used. The smaller foot valves are usually hand operated but can be driven by an electric pumping mechanism.

VOC Sample Collection

Both standard and high flow foot valves can be used for VOC sampling. In addition to the foot valve and tubing, about seven feet of 0.25 inch diameter VOC tubing is required.

After the well has been purged, the seven feet of additional tubing is inserted inside the pumps main tubing leaving about one foot protruding out the end. The pump is then operated until water is flowing from both tubes. When pumping is ceased, due to a siphon action, water will continue to flow from the smaller diameter tubing until it draws down to the level of water in the pumps tubing. This flow can easily be used to collect small undisturbed VOC samples.

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