Water Sampling

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Water Sampling

Submersible pumps for purging and sampling groundwater monitoring wells. The shop stocks the Eijkelkamp Gigant submersible pump for regular monitoring work and a low cost submersible pump set for lighter duty or as a spare. Supplied direct from our UK operation.

Gigant Submersible Pumps

Gigant Submersible Pump

£207.00
The Submersible Pump Set - Low Cost kit features sensors with wires, control units, screws, and coiled tubing, all arranged on a white background.

Submersible Pump Set – Low Cost

£889.00

Pumps in stock

  • Gigant Submersible Pump — the more capable unit, suited to regular purging rounds, deeper wells and jobs where you need to move a meaningful volume of water reliably.
  • Submersible Pump Set — Low Cost — a lighter duty set for occasional sampling, smaller programmes, or as a backup so a single pump failure does not cancel a monitoring round.

Purging before you sample

Water that has been standing in a well casing since the last visit is not the water you want to analyse. It has exchanged gases with the air in the casing, it has been in contact with the pipe, and its dissolved oxygen, redox potential and volatile content will have drifted away from aquifer conditions. Sampling it produces a number that describes the borehole rather than the groundwater.

Purging removes that stagnant water so the sample is drawn from formation water entering the screen. How much to remove depends on the method you are working to: purging several casing volumes is the traditional approach, while low-flow purging pumps gently and monitors field parameters until they stabilise. Low-flow generally gives less turbid samples and produces far less purge water, which matters on contaminated sites where that water needs disposing of properly.

Sizing the well around the pump

A common and expensive mistake is installing narrow monitoring wells, then discovering they will not take a pump. A water level meter needs almost no clearance, so a slim well seems perfectly adequate at the design stage. A submersible pump needs considerably more. If your programme includes sampling as well as dipping, decide on the pump first and specify the well pipe around it.

Tubing and cross-contamination

Whatever the pump touches in one well travels to the next. On contaminated land work that is the fastest way to produce a dataset nobody can defend. Decontaminate the pump body between wells, and either dedicate tubing to each well or replace it between wells — PE and silicone tube is inexpensive enough that a fresh length per well costs less than repeating a sampling round. Ball valves in the same section control flow at the surface without disturbing the pump.

Related equipment

For the wider groundwater pump range including peristaltic and higher capacity units, see Groundwater Pumps. Where the method calls for a bailer or a discrete depth sampler rather than a pump, see Liquid Samplers. For recording levels before and during purging, see Water Level Meters and Water Level Loggers.

Water sampling FAQs

Water standing in the casing between visits is not representative of the aquifer. It has been in contact with air and with the pipe, so dissolved oxygen, redox and volatile determinands will all have drifted. Purging draws that stagnant water out so the sample you collect is groundwater that has just entered the screen.
The traditional approach is to remove several casing volumes; the low-flow approach is to pump gently and monitor field parameters until they stabilise. Which you use is usually set by the standard or the client specification you are working to, so check that first. Low-flow generally produces less turbid samples and far less purge water to dispose of.
The Gigant submersible pump is the more capable unit and the sensible choice where you are purging regularly, working deeper wells, or need to move a meaningful volume. The low cost submersible pump set is aimed at lighter duty and occasional use, or as a spare so a single failure does not stop a monitoring round.
The pump, not the meter, sets the minimum well diameter. Narrow wells that are perfectly adequate for dipping with a water level meter may be too tight for a pump. If you are installing new wells and intend to pump them, decide on the pump first and size the pipe around it.
Decontaminate the pump and change or dedicate the tubing between wells. On contaminated land work, dedicated tubing per well is the safest approach - PE and silicone tube are inexpensive enough that a fresh length per well is cheaper than an invalidated sampling round.
In most cases yes, and for volatiles a pump is usually preferable because it avoids the agitation and aeration a bailer causes on retrieval. Where a bailer or dedicated liquid sampler is required by the method, see our liquid samplers range instead.
Tubing to bring the sample to surface, a power source appropriate to the pump, and somewhere to put the purge water. On a contaminated site the disposal route for purge water needs deciding before you arrive, not after you have produced twenty litres of it.

Ordering and support

Pumps listed here are genuine Eijkelkamp equipment supplied direct from our UK operation. Tell us your well diameter, typical water depth and whether you are working to a low-flow protocol, and we will confirm which pump suits the programme before you order.

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