How Much Water Does a Pig Need?

Water is the nutrient every pig guide mentions in passing and almost none puts a real number on. Our own feed guide notes that a pig can drink up to 20 litres a day — but that's one pet-pig charity's figure for an average adult, and the published range across sources is much wider than that single number suggests.

AHDB's figures, by weight and stage

AHDB, the UK levy body whose figures already underpin the feed guide, publishes an estimated daily water requirement table by pig type:

These are the figures AHDB uses alongside minimum nipple-drinker flow rates for commercial systems — a design baseline as much as a consumption forecast, which is worth knowing before comparing them to the higher figures below.

Other sources publish noticeably higher figures

The Pig Site's own water guidance gives a different table: weaners at 3–5 litres, growers at 5–7 litres, finishers at 9–12 litres, and dry sows and boars at 12–15 litres a day — two to three times AHDB's finishing-pig figure above. In the US, the Pork Information Gateway and Kansas State University Extension both describe grow-finish pigs drinking roughly 6–12 litres a day (1.5–3 gallons), with water-to-feed ratios typically 2:1 to 3:1 by weight and declining as pigs grow, and lactating sows drinking as much as 20–38 litres a day (5–10 gallons).

We're not picking a winner between these: they're measuring genuinely different things — design minimums, typical consumption, and consumption at higher temperatures — and none of them is wrong. The practical takeaway is the same regardless of which table you read: a growing pig's daily intake is somewhere in the low single digits of litres, a lactating sow's is in the tens of litres, and the published range within each category is wide enough that a fixed daily allowance is the wrong way to plan. Constant access to fresh water is the actual requirement, not a number to ration to.

Heat matters more than almost any other factor

The Pig Site reports that finisher pig water intake roughly doubled — from 2.2 to 4.2 litres a day — as ambient temperature rose from 10°C to 25°C. Pigs can't sweat effectively, so water does double duty as both a nutrient and a cooling mechanism; demand climbs sharply in hot weather, exactly when a summer keeper is least likely to be checking a trough twice a day. If you're planning for outdoor pigs, see our guide on keeping pigs outside in summer and winter.

What this means for a backyard or smallholding setup

• Provide constant access to clean water rather than a measured daily amount — every source agrees on this even where the numbers disagree.
• Check troughs and drinkers at least twice a day in hot weather, when intake can double, and pigs can empty or foul a container faster than expected.
• In freezing weather, check drinkers haven't iced over — pigs will reduce feed intake if water access is restricted, even briefly.
• A wallow (where you can provide one) helps with cooling separately from drinking water, and reduces how hard drinking water has to work as the only cooling source.

Sources: AHDB, “Water quality and quantity”; The Pig Site, “Water: The Forgotten Nutrient in Pigs”; Pork Information Gateway, “Water Recommendations and Systems for Swine”; Kansas State University Extension, swine nutrition guide, water requirements; Every Pig Rescue Service (cited in our feed guide). Sources checked: September 2026.

Common questions

How much water does a pig drink a day?

It depends heavily on size, diet and especially temperature — published figures for a full-grown pig range from around 2 litres a day up to 20 litres or more in hot weather. There's no single reliable number, which is exactly why constant access to fresh water matters more than sizing a fixed daily allowance.

Why do different sources give such different water figures?

Mostly because they're measuring different things: some figures are minimum drinker-system design flows, others are typical consumption in mild conditions, and others are consumption in hot weather. None of them are wrong, they're just answering slightly different questions — which is why this guide shows the range rather than picking one.

Does hot weather really make that much difference?

Yes. One industry source found finisher pig water intake roughly doubled, from 2.2 to 4.2 litres a day, as ambient temperature rose from 10°C to 25°C. Pigs can't sweat effectively, so they rely on water for cooling as well as drinking, and demand rises sharply in summer.

Is there a water calculator on this site?

Not yet. The published figures vary too widely by source, temperature and system to turn into one defensible number the way pen size or feed cost can. If a single citable standard turns up, a calculator is a natural addition.

The water calculator turns these figures into a daily and weekly total for your pigs.