The Waterra Standard Flow System is the most popular Waterra (inertial) Pump. This system is best suited for 25mm inch to 50mm ID monitoring wells and can provide lifts of 45m to 60m. Flow rates can be as much as 3.7 liters per minute. Foot valves / check valves consist of a check ball inside the valve body, available in stainless steel, size 16 mm OD x 12.5 mm ID (5/8 x 1/2) diameter. Tapered threads enable the foot-valve to self-tap onto either end of the sample tubing. The Standard Flow System is suitable for a variety of sampling environments.

A Waterra SS-16 Foot Valve (316 Stainless Steel) threads into Standard Flow Tubing for sampling narrow diameter piezometers.

The SS-16 Foot Valve is best used for narrow diameter wells as the Outside Diameter of the Valve is 16 mm (5/8 inch). It would fit nicely in a 1 inch ID well for instance.

The Waterra SS-16 Foot Valve is recommended when there is concern about chemical inertness.

An Acetal Thermoplastic (Delrin) alternative is the D-16 Foot Valve which also threads into the ID of the tubing.

For 2 inch wells we would normally recommend a D-25 Foot Valve.

The Standard System with an SS-16 Foot Valve can provide lifts of 150 feet (45 m). Flow rates can be as much as 1 gallon per minute (4.5 lpm).