Question 1

How big a water trough does a dairy cow need?

Accepted Answer

A lactating dairy cow needs approximately 80–120 litres of water per day (average 100 L), with peak intake after milking. As a rule of thumb, allow at least 10% of your daily demand as trough storage capacity if you have a fast supply, or up to 35% of daily demand if your supply is slow. For a 100-cow herd, that means at least 1,000–3,500 litres of trough capacity. This calculator works it out based on your actual flow rate.

Question 2

How much water do sheep drink per day?

Accepted Answer

Dry ewes drink around 3–5 litres per day in temperate conditions. Lactating ewes can drink up to 8–10 litres. In very hot weather or on dry summer pasture, demand rises sharply. Sheep mob-drink — the whole group tends to drink at once — so trough capacity and trough length are especially important. Allow at least 35 cm of trough length per animal that might be drinking at one time.

Question 3

What flow rate do I need for a cattle trough?

Accepted Answer

As a minimum, your supply should be able to refill the trough between peak drinking events. For cattle, that means being able to supply the daily demand in no more than 12 hours (half the day), so the float valve has time to refill overnight. For 50 beef cattle drinking 38 litres each = 1,900 L/day. At 2 L/min flow, that takes 15.8 hours — borderline. At 3 L/min (180 L/hr), it takes 10.6 hours — adequate. This calculator checks your flow rate automatically.

Question 4

How long should a cattle trough be?

Accepted Answer

Allow at least 50–65 cm of trough length per animal that might be drinking simultaneously. For dairy cows (typically 15–20% of the herd at peak) in a 100-cow herd, that is 15–20 cows × 0.65 m = 9.75–13 m of trough. In practice, split this between two or three shorter troughs in different locations to reduce competition and bullying. The calculator gives you the minimum total trough length and lets you divide it across multiple troughs.

Question 5

How do I stop my trough freezing in winter?

Accepted Answer

There are several approaches: a submersible trough heater (25–100 W depending on trough size and exposure) keeps the water just above freezing; insulation lagging on the trough body slows heat loss; positioning the trough in a sheltered building or against a hedge reduces wind chill. Float valve supply pipes should be lagged or routed underground to prevent freezing. For field troughs on a slow supply, a larger insulated trough acts as a thermal buffer overnight.

Question 6

Why does trough length matter as much as trough volume?

Accepted Answer

Cattle and sheep establish a pecking order at the trough. If subordinate animals cannot access the water because dominant animals are blocking the trough, they become dehydrated even if plenty of water is available. Trough length (linear drinking space) determines how many animals can drink simultaneously. As a minimum, size your trough to allow the top 20–35% of the group to drink at the same time without blocking others.

Question 7

How do I measure my water inlet flow rate?

Accepted Answer

The simplest method: time how long it takes to fill a known vessel through the inlet pipe (not from the trough when the float valve is open — measure directly from the pipe). A 10-litre bucket filled in 5 seconds = 2 litres per second = 120 L/min. For slower supplies, use a larger container (e.g. a 100-litre drum). Divide litres by seconds, then multiply by 60 to get L/min. Most farm water supplies to field troughs range from 1–10 L/min.

Question 8

How many troughs do I need?

Accepted Answer

For housed cattle, provide at least one trough per 20–30 animals, located away from the feed barrier so animals are not competing for feed and water at the same time. For sheep on pasture, provide at least one trough per 200–300 ewes, or more if the field is large and some animals have to travel far to drink. In hot weather, additional troughs reduce stress and maintain intake. This calculator lets you specify the number of troughs and divides the load accordingly.

Question 9

Does water demand change with the weather?

Accepted Answer

Yes, significantly. Dairy cows may drink 150+ litres per day in hot weather compared to 80 in cool conditions. Lactating beef cows on dry summer pasture can need 70–80 litres. Sheep on lush winter grazing may barely use the trough (grass provides most of their water), but on dry summer pasture or in housing they can need 2–3× their winter intake. The demand figures in this calculator are mid-range estimates for temperate UK conditions — add a 20–30% buffer in summer.

Livestock Type	Daily Intake	Peak Session	Trough Space
Dairy Cow (lactating)Cattle	100 L/day	~35 L	0.65 m/animal
Dairy Cow (dry period)	60 L/day	~21 L	0.65 m/animal
Beef Cow (adult)	55 L/day	~19 L	0.55 m/animal
Beef Store (300–500 kg)	38 L/day	~13 L	0.50 m/animal
Beef Store (150–300 kg)	22 L/day	~8 L	0.45 m/animal
Weaned Calf	12 L/day	~4 L	0.35 m/animal
Ewe (maintenance)Sheep	4 L/day	~2 L	0.35 m/animal
Ewe (late pregnancy)	5.5 L/day	~2 L	0.35 m/animal
Ewe (lactating)	8 L/day	~4 L	0.35 m/animal
Hogg / Gimmer	3 L/day	~1 L	0.30 m/animal
Store Lamb	2 L/day	~1 L	0.25 m/animal
Sow (lactating)Pigs	25 L/day	~6 L	0.50 m/animal
Grower Pig (50–100 kg)	6 L/day	~2 L	0.25 m/animal

Livestock Water Trough Calculator

Trough Size Calculator

Daily Water Demand Reference

How the Calculation Works

Winter Water Provision & Frost Protection

Frequently Asked Questions