How Much Water Does a Cow Drink a Day? A UK Farm Guide
Published by SEO Dons · Last reviewed October 2026
Ask how much water a cow drinks and the honest answer is “it depends” — on whether she is milking, how much milk she gives, what she is eating and how hot it is. But a farm planning a water supply needs numbers, not caveats, so here are the sourced figures, the peaks to design for, and what they mean for troughs, licences and pumps.
The averages
The most complete published table we have found comes from the Ontario Ministry of Agriculture, Food and Agribusiness (“Water requirements of livestock”, updated 6 May 2026). Its averages, in litres per animal per day:
| Animal | Average litres a day |
|---|---|
| Dairy cow, milking | 115 |
| Dairy cow, dry | 41 |
| Beef cow with calf | 55 |
| Beef cow, dry, or bull | 38 |
| Finishing cattle | 41 |
The milking figure is the one that surprises people. A cow turning feed into milk needs the water to make it, so a milking cow drinks nearly three times what a dry cow does.
The peaks to design for
Averages are for budgeting; supply has to be sized for the worst day. Water engineers at Penstar, quoted by Farmers Weekly, put the total water need per cow at up to 170 litres a day on a hot summer’s day, and note that the milking parlour can use around 70 litres per cow a day for washing.
They also give a rule for troughs: size the trough at half the one-hour demand. For a 400-cow herd that is 5,600 litres an hour, so each paddock needs at least 2,800 litres of trough capacity — two 1,400-litre troughs, for example — and a supply that can refill them quickly.
What a herd adds up to
Multiply out and the totals get large quickly:
- 150 milking cows at 115 litres = 17.25 cubic metres a day, before any parlour washing.
- Add 70 litres a cow for the parlour and the farm is using about 27.75 cubic metres a day.
- 100 suckler cows with calves at 55 litres = 5.5 cubic metres a day.
Those numbers matter if the water comes from the farm’s own borehole, spring or stream rather than the mains. In England you are likely to need an abstraction licence above 20 cubic metres a day, and in Wales the exemption is 20 cubic metres a day per source of supply — so a 150-cow dairy herd drawing its own water can cross the line once parlour use is counted. Our guide to water abstraction licences on farms sets out the rules in each nation.
Getting the water to the trough
Distance and height are what make field water expensive. A trough at the top of a hill needs a pump; a trough a kilometre from the yard needs either a long trench for a pipe and a cable, or power generated on the spot. That is where solar fits: the pump runs while the sun shines, fills a header tank, and the tank feeds the troughs by gravity.
The sizing follows directly from the water figures above. Lifting 1,000 litres by 1 metre takes 9.81 kJ of energy, so 100 suckler cows’ 5.5 cubic metres lifted 25 metres needs about 0.37 kWh of lift a day, or roughly 0.94 kWh from the panels if the pump set converts 40% of its input into lift. Our guide to choosing a solar water pump for livestock works that example through, month by month, with PVGIS output figures.
Water quality and access
Quantity is only half the job. Clean troughs, enough trough space for the group and a refill rate that keeps up with a busy hour all help stock drink what they need, which is why the engineers’ rule sizes troughs on the peak hour rather than the daily total.
Sources
- Ontario Ministry of Agriculture, Food and Agribusiness, “Water requirements of livestock” (updated 6 May 2026).
- Farmers Weekly, “Guide to planning water requirements on your dairy farm” (updated 19 January 2021), quoting Penstar water engineers.
- gov.uk, “Check if you need a licence to abstract water” (updated 2 July 2026); Natural Resources Wales abstraction guidance.