Stock water requirements: how much water does your block actually drink?

💧 The short version

Most people underestimate it, and the failure is never the tank.

Ask a small-block owner how much water their animals drink in a day and most cannot say. It is not a criticism — water sits in a trough being reliable for eleven months of the year, so there is no reason to have worked it out.

The trouble is that when a water system fails it does so at the worst possible moment: a hot afternoon, on dry feed, when demand is at its highest and everything is hardest to fix. And the failure is almost never an empty tank. It is a seized float valve, a leak nobody found, a pump that died on a Friday, or a trough that refills more slowly than a mob drinks.

All of those are cheap to find in spring and expensive to find in summer. This guide covers what the published figures actually say, why New Zealand and Australian sources give very different answers, and what is worth checking before the ground dries out.

🇳🇿 The numbers

How much water do farm animals drink? The New Zealand figures.

New Zealand's most useful published set comes from a 2022 review prepared for Horizons Regional Council by Aqualinc Research, which pulled together regional council allowances, industry figures and research literature to recommend standard stock drinking water requirements.

It reports two numbers for each animal, and the distinction matters more than any single figure:

• ADD — average daily demand. Total annual consumption divided by 365. This is the planning number for a whole year.
• PDD — peak daily demand. The highest single day of the year. This is the number your system has to survive, and it is the one to design troughs and flow around.

For deer, the review declined to recommend a national figure and instead pointed to the values used by Canterbury and Southland Regional Councils — hinds 30 L average and 45 L peak, stags 20 L and 30 L.

For horses and goats, the review found no recent New Zealand research and no council figures at all, so it left them out. That gap is real, and it is one reason the Australian table below is worth having.

🇦🇺 The numbers

The Australian figures, and why a New Zealander should look at them.

Agriculture Victoria publishes a stock water table that covers the two categories the New Zealand review left blank, and reports a summer figure alongside the average:

Agriculture Victoria also names the four things that move these numbers: the class of animal, the temperature and season, the feed on offer, and the quality of the water. Two of those are worth holding onto.

Stock drink considerably more on dry feed — grain, hay, dead pasture — than on green pasture with high water content. So demand climbs at exactly the point in the season when supply gets harder. That is the whole reason summer catches people out: it is not simply that it is hot, it is that the feed stops carrying water for you.

And salty water increases consumption. If you are on a bore, that is not a footnote.

🔍 The disagreement

Why do the New Zealand and Australian figures disagree so badly?

Put the two tables side by side and something jumps out. New Zealand's peak figure for a ewe is 4.5 litres a day. Agriculture Victoria's summer figure for a ewe with lambs is 14 litres — more than three times as much. Adult cattle are 70 litres peak in the New Zealand table and 112 litres in summer in the Victorian one.

Both are current. Both come from a credible authority. A smallholder reading both would reasonably conclude one of them must be wrong.

Neither is wrong. They are answering different questions.

• The New Zealand figures are consenting figures for New Zealand conditions. They were produced so a regional council could judge a reasonable water take, on a green-pasture system, in a maritime climate where stock get a meaningful part of their water from the grass itself. The ewe figure is also specifically a ewe, not a ewe with lambs at foot.
• The Victorian figures are summer figures for a hotter, drier place, on feed that has dried off, for a class of animal — ewes with lambs — that is lactating and therefore drinking far more.

Once you see that, the gap stops being a contradiction and becomes the single most useful thing on this page: the number you need is not a fact about your species, it is a fact about your season, your feed and your class of stock.

🧮 Your own number

Working out what your block drinks in a day.

Multiply out, add up, and write the answer down. Take a small mixed block with twenty ewes with lambs at foot, two dry cattle, one horse and a dozen hens.

On the New Zealand peak figures: ewes 20 × 4.5 = 90 L, cattle 2 × 70 = 140 L, hens 12 birds at 45 L per 100 ≈ 5 L. The horse is not in the New Zealand table, so borrow Victoria's 49 L. Total: roughly 284 litres a day.

On the Victorian summer figures: ewes with lambs 20 × 14 = 280 L, adult dry cattle 2 × 112 = 224 L, horse 49 L, hens ≈ 5 L. Total: roughly 558 litres a day.

Two defensible answers, and one is nearly double the other. That is not a reason to distrust both — it is the range your system needs to cope with across a year, and knowing the top of it is the point of the exercise.

Most people guess low, and usually by a lot. Half a tonne of water a day, moving quietly through a pipe nobody has inspected, is a very different mental picture from "the sheep have a trough".

🚱 The hidden number

A surprising amount of what you pump never reaches an animal.

This is the finding in the New Zealand review that deserves to be better known. All of its figures include leakage — losses from the pipe network on the way to the trough — because leakage is not a rounding error.

The review cites research finding that more than 21% of stock drinking water is lost to leakage, with individual farms ranging from 2% to 61%. DairyNZ figures quoted in the same report put leakage at 29–47% of water measured at the pump on non-irrigated farms.

Those are commercial farms with maintained systems. A lifestyle block running older pipe, joins of varying vintage and a trough or two installed by a previous owner has no particular reason to do better.

The practical consequence: if the animals seem to be getting through far more water than the tables suggest, the extra is not necessarily being drunk. Look for it in the ground before you conclude your stock are unusually thirsty — and if you have a water meter, a reading taken when every animal is shut away from every trough tells you a great deal in ten minutes.

🚰 The common mistake

Trough refill rate matters more than trough size.

A trough is a buffer, not a supply. What actually determines whether every animal gets a decent drink is how fast the trough refills, because stock do not drink evenly through the day. They come as a mob, typically in the afternoon, and they drink hard.

Twenty ewes with lambs arriving at a forty-litre trough will empty it in minutes. From that moment everyone is drinking at whatever rate the pipe delivers — and the animals still waiting are the ones lowest in the pecking order: the smallest, the shyest, the youngest.

This is a failure mode that never looks like one. The trough is full whenever you walk past in the morning. There is simply a lamb that is not doing as well as its twin, for reasons that get put down to something else.

For a sense of scale, DairyNZ guidance for dairy cattle talks in terms of flow per animal per hour rather than trough volume — the useful habit to borrow is thinking in litres per hour delivered, not litres held.

How to test it: empty the trough deliberately, then time how long it takes to refill. That gives you a real delivery rate you can compare against the mob that uses it. A trough that takes a long while to come back is worth knowing about in September rather than January.

🧪 Quality

Clean, cool and low in salt — and what to do about algae.

Agriculture Victoria's guidance is that stock do best on water that is fresh, cool and clean — low in salt, low in organic matter, low in suspended clay, and free of toxic substances such as blue-green algae.

Three things follow for a small block:

• Warm water gets drunk less. A trough in full sun all afternoon is doing you no favours in January. Shade is a genuine improvement, and planting a tree or shifting a trough is a spring job, not a summer one.
• Scrub the algae out before the water warms. Growth accelerates as temperatures climb, and a trough cleaned in September stays manageable far longer than one first tackled in December. Blue-green algae in dams and open water is a serious animal-health risk, not merely unsightly — if you have surface water your stock drink from, know what it looks like and who to ring locally.
• If you are on a bore, salinity is worth knowing. Agriculture Victoria publishes tolerance levels by class of stock — production decline begins for beef cattle around 4,000 mg/L total dissolved solids, and lactating ewes and weaners are less tolerant than dry mature sheep. Salty water also increases how much stock drink, which compounds a supply problem rather than easing it.

🛢️ Storage

How many days of water do you actually have?

Almost nobody has done this sum, and it takes about thirty seconds once you have your daily number.

Tank capacity ÷ daily demand = days of supply if the pump or the source stops today.

Using the mixed block above at its summer figure of roughly 558 litres a day, a 25,000-litre tank that happens to be half full holds about 22 days of stock water. The same tank at a quarter full, in a week where demand runs higher than you assumed, is a different and much shorter story.

Two things worth adding to the calculation:

• Household use, if the animals share your tank. On many small blocks they do, and that changes the arithmetic considerably.
• The leakage figure above. If a fifth or more of what leaves the tank never reaches an animal, your days of supply are correspondingly fewer.

You do not need a precise answer. You need to know whether you are in the region of five days or fifty, because the two call for entirely different responses.

🔧 Do these now

Four checks worth doing in spring, not summer.

The case for doing this work early is simple: everything that makes a water system easy to inspect is available in spring and gone by midsummer. The ground is soft, so a leak shows. Demand is low, so a trough can be run dry deliberately without any animal suffering for it. And there is time.

• 1. Time a refill. Empty each trough and time how long it takes to come back. That is your real delivery rate, and it is the number that decides whether the tail of the mob gets a drink.
• 2. Work every float valve by hand. They seize, they stick part-open, they drip. All three are trivial in September and awkward in February.
• 3. Walk the pipe lines. On soft ground a leak shows as a green stripe or a wet patch while everything around it dries. The same leak in January is invisible and has been running for weeks.
• 4. Do the storage sum. Days of supply if the source failed today. Write the answer somewhere you will see it again.

While you are there: scrub troughs out, check that every paddock you intend to graze in summer actually has working water in it, and note any trough sitting in full sun.

🌏 Season

Planning for a dry summer without overclaiming.

Seasonal forecasts are worth watching and worth handling carefully. Climate drivers such as El Niño shift the odds of a dry season in parts of both countries — in New Zealand the broad El Niño pattern tends to be drier in the east, wetter on the West Coast and windier generally — but a signal in the Pacific does not translate directly into what happens at your gate.

For current outlooks, go to the source rather than to a headline: NIWA publishes New Zealand's seasonal climate outlook, and the Bureau of Meteorology publishes Australia's long-range forecasts. Both update regularly, and both are more careful about uncertainty than most reporting of them.

The honest framing for water planning is that you do not need a forecast to justify the work on this page. Checking a float valve and timing a trough refill are worth doing in an average year. A dry outlook simply raises the cost of not having done them.

📝 Records

What to write down.

Water is mostly infrastructure rather than record-keeping, but three things are worth capturing because they are impossible to reconstruct later:

• Your daily demand figure and the date you worked it out. It goes out of date every time you change stock numbers, and a figure with a date on it tells you when to redo it.
• Trough refill times, per trough. Measured once, they become a baseline. A trough that used to refill in two minutes and now takes six is telling you something.
• Rainfall. The value of a rainfall record is entirely retrospective. Next February, "is this drier than last year, or does it just feel like it?" is either a number or an argument with yourself.

A tip worth the ten seconds: write your daily water number on the tank itself, in permanent marker, with the date. It turns an abstract worry into a sum you can do at a glance, and when you add stock next season the number sits there being visibly wrong until you update it. The best farm records are the ones physically in the way.

📚 Further reading

Where the information on this page comes from.

• Horizons Regional Council / Aqualinc Research — Stock Drinking Water Requirements (2022) (PDF): the New Zealand average and peak daily demand figures for dairy, beef, sheep, deer, pigs and chickens, the note that all values include leakage, and the leakage research cited in this guide.
• Agriculture Victoria — Useful Tables: Stock Water: the Australian summer and average figures for sheep, beef cattle and horses, the four factors that change consumption, the fresh/cool/clean guidance and the salinity tolerance levels.
• Agriculture Victoria — Stock water requirements: background on planning farm water supply.
• DairyNZ: dairy-specific water use and flow-rate guidance, and the leakage figures quoted in the Horizons review.
• NIWA — Seasonal Climate Outlook: New Zealand's current three-month outlook.
• Bureau of Meteorology — Australian climate outlooks: Australia's long-range rainfall and temperature forecasts.