Water for horses: how much and how to provide it

Water is the most important thing you give your horse, and the easiest to take for granted. A trough that has quietly stopped filling, a bucket kicked over overnight, or a dam turning bad in a dry spell can become an emergency within a day.

Both countries treat water as a minimum welfare standard. Victoria's Code of Practice requires horses to have free access to an adequate supply of good quality water, enough to meet their daily needs and keep them healthy (Code of Practice). New Zealand's Code of Welfare requires access to a reliable daily supply of drinking water that is palatable, sufficient and not harmful to health (MPI Code of Welfare).

How much water does a horse drink?

Victoria's Code gives a basic maintenance requirement of about 52 ml per kg of bodyweight per day, with these examples (Code of Practice):

Horse type	Bodyweight	Water per day (maintenance)
Ponies	200–300 kg	10–15 litres
Light hacks	300–450 kg	15–25 litres
Thoroughbreds	450–500 kg	25–30 litres

Those are minimum maintenance figures for a horse at rest. The Code says needs increase with growth, work and lactation, and that horses in work need two or three times as much. Agriculture Victoria's feeding guidance gives a similar rule of thumb – ponies may need 15 litres a day and horses 30 litres – and notes this can double in hot weather or with exercise (Agriculture Victoria – feed requirements).

What changes how much a horse drinks

Victoria's Code says water needs vary widely with age, bodyweight, air temperature and humidity, work, health and diet (Code of Practice):

• Diet: water need is closely linked to how much dry feed a horse eats – about 2–4 litres of water per kilogram of dry matter. A horse on hay drinks more than one on lush grass.
• Heat and humidity: requirements rise as temperature or humidity rises.
• Work: horses in work need two to three times the maintenance amount.
• Illness: bowel disease such as obstructive colic or severe diarrhoea can cause large losses of water and electrolytes – 50–70 litres a day.

New Zealand's Code adds that water needs rise when horses graze dry summer pasture (MPI Code of Welfare).

Estimate your horse's needs

Stable Guide's feeding calculator estimates your horse's weight from tape measurements and gives a rough daily water figure. Treat it as a minimum starting point, not a target – your horse should always have more available than it needs. To measure your horse, see how to measure a horse's height and weight.

Troughs, buckets, automatic drinkers and dams

Victoria's Code recommends that water containers and mechanical water sources are (Code of Practice):

• Inspected at least daily to make sure they're working
• Secured and non-spillable
• Kept clean and working properly
• Of a design that can't injure horses (a minimum standard)

Troughs

Troughs suit paddock horses. New Zealand's Code recommends watering facilities are designed to reduce fouling and wastage, and that troughs are cleaned often so water is available and uncontaminated (MPI Code of Welfare). It also expects reticulation systems to be monitored and maintained, with any delivery failure fixed immediately.

Practical checks:

• Watch the float valve work, don't just glance at the water level.
• Scrub out algae, leaves and droppings regularly.
• Check for sharp edges and exposed pipes.
• Make sure timid horses can drink without being pushed off. In a group, a second water point helps.

For trough placement and shade, see shelter and water in the paddock.

Buckets

Buckets are common in stables and yards, but they run out and get knocked over. Victoria's Code recommends that where water is supplied in buckets, the supply is checked at least every 12 hours (Code of Practice). In practice that means more than one bucket, secured so they can't be tipped, and topped up morning and night. Buckets also let you see exactly how much a horse is drinking, which is useful when it's unwell.

The BHS Stage 1 syllabus covers providing water by bucket or automatic drinker, where to position the bucket and how often to clean it (BHS Stage 1 Care).

Automatic drinkers

Automatic drinkers save labour, but you can't see how much a horse is drinking, and a blocked or broken one may go unnoticed. Check daily that each one is working, and clean the bowls often.

Dams and natural water

Victoria's Code recommends dams have safe access for horses and are kept free of rubbish and contaminants, and that dam levels and water quality are watched closely during low rainfall (Code of Practice). Boggy edges can trap horses, and water quality can drop as levels fall. Where you can't provide enough water for health, the Code's minimum standard is that horses must be moved, agisted, sold or euthanased.

Keeping water clean and safe

New Zealand's Code expects water quality to be monitored so it doesn't contain contaminants at harmful levels (MPI Code of Welfare). If you rely on bore, dam or recycled water, ask your vet or local agriculture department about testing.

Disease and shared water

Shared water can spread disease. An international consensus on strangles notes the bacterium can survive in water for 4–6 weeks, and recommends no sharing of water between groups during an outbreak (ACVIM strangles consensus). At shows, bring your own buckets rather than using communal troughs. See biosecurity and isolating new horses.

In Hendra areas of Australia, NSW DPI advises that the risk of transmission can be further reduced by covering feed, and recommends Hendra vaccination as the most effective protection (NSW DPI – Hendra virus). Australia's national public health guidelines for Hendra also suggest placing feed bins and water troughs under cover and away from areas where flying foxes feed or roost (CDNA Hendra virus guidelines). See horse vaccinations.

Signs a horse isn't drinking enough

New Zealand's Code lists as a welfare indicator that horses have enough water to stay healthy and show no signs of dehydration (MPI Code of Welfare). Warning signs include:

• Water levels not going down as usual
• Dry, firm or reduced manure
• Dullness or reduced appetite
• Signs of colic

A horse that has stopped drinking needs attention. See horse colic and signs of a healthy horse, and call your vet if you're concerned.

Water when travelling

Horses often drink less away from home. Victoria's Code allows an exception to the free-access water standard only while horses are being transported in line with Victorian land transport laws (Code of Practice) – so plan for water at every stop and on arrival.

We haven't found an Australian or New Zealand authority that sets how often to offer water on a trip, so we don't give a figure here. Practical tips many owners use:

• Carry water from home and familiar buckets.
• Offer water at rest stops and as soon as you arrive.
• Get your horse used to drinking from your travel buckets at home first.

See long-distance travel and horse float safety checks.

Daily water checklist

Pony Club Australia puts water first on its daily paddock checklist (PCA Syllabus):

• Every trough, bucket and drinker is full and working
• Water is clean – no algae, droppings, dead animals or debris
• Buckets checked at least every 12 hours
• Float valves and pipes working; no leaks
• Dam access safe and water level adequate
• Extra water available on hot days and for working horses

FAQ

How much water does a horse drink a day?

At rest, Victoria's Code estimates about 52 ml per kg of bodyweight – for example 25–30 litres for a 450–500 kg Thoroughbred (Code of Practice). Needs can double or triple with heat and work.

Is a trough or bucket better?

Troughs suit paddocks; buckets suit stables and let you see intake but need checking at least every 12 hours (Code of Practice). Whatever you use, keep it clean and secure.

How often should I clean my horse's trough?

New Zealand's Code says troughs should be cleaned often to keep water uncontaminated (MPI Code of Welfare). Check them daily and scrub when dirty.

Does a horse drink more on hay than grass?

Generally yes. Victoria's Code links water need to dry matter intake – 2–4 litres per kilogram (Code of Practice).