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Water systems – very big troughs not the solution

Water systems – very big troughs not the solution

Along with suitable paddocks and roadways, the role of a suitable water system in good grazing infrastructure can’t be overlooked. Factors such as adequate pipe sizes, suitable ballcocks, the size and location of water troughs, and the water flow rate all needed to be factored.

A flow rate of 0.2 litres per cow per minute and a trough volume of about 5-7 litres per cow is generally recommended. For example, a flow rate of 20 litres per minute and approx. 600 litre troughs per 100 cows.

Don’t be tempted to solve water supply problems with very big troughs; focus on flow rates and larger pipe sizes instead. Farms vary widely in terms of cow numbers, pipe length, farmyard location and topography, so take all these factors into account when deciding on pipe size and system layout.

The aim is to minimise pressure loss due to friction in water pipes so that enough pressure is available to overcome elevation changes and maintain a good flow rate in troughs. Err on the high side with pipe size bore.

A ring main (loop system) is a cost effective way to enhance water flow rates and ensure an even flow rate to troughs. Main pipe size bores should typically be 25mm, 32mm or 40mm and branch pipe bores to individual troughs should be 20mm, 25mm or 32mm.


Use “full flow” type ballcocks in all new troughs. These ballcocks typically have 9-12 mm jets, providing a good flow rate even with low pressures at the ballcock. A standard high pressure ballcock jet (3 mm diameter) is very restrictive even where pressure at the ballcock is high.


Position troughs to minimise walking distances to water and to avoid unnecessary smearing of grass. Keep troughs away from gaps and hollows. Troughs should be level and have no leaks. Isolate, monitor, locate and repair leaks. Troughs on roadways will slow cow movement and make roadways dirty. Allow trough space for at least 5% of the herd to drink at once. Assess costs in advance; costs can amount to €300 per hectare for new installations.

This article was adapted from the paper titled: Planning for good grazing infrastructure’ which first appeared in the Moorepark Open Day 2023 booklet and was written by Tom Fallon, Pat Tuohy and Paul Maher. Access the full publication here.

Farmers must also be aware of the regulations pertaining to the location of water troughs to protect water quality. More information is available on this topic in the below article:

Also read: Water trough location and water quality