Cleaning and Sanitising Poultry Water Tanks

Lift the lid and see what the last clean missed

Lift the lid on a tank that has gone too long without cleaning, and the first thing you notice is the smell, a flat, earthy sourness that is not the smell of water. Look closer and there is a dark layer on the floor, flakes of rust on the walls, and sometimes a dead gecko or a drowned beetle lying in the outlet corner. The water on top may still look clear, which is exactly why the tank gets neglected.

Four things build up in a poultry tank, and each one comes from a different source. Algae grows wherever light reaches the walls, so a tank in the sun or a tank with a clear window grows green in weeks. Sludge is the fine material that washes off the roof or blows in through the vents: dust, leaves, feathers and bird droppings. Scale is the white crust that hard water leaves behind, which narrows pipes and blocks nipples. Rust comes from steel tanks where the coating has worn through. None of these is dangerous on its own, but all of them give bacteria a place to multiply and give the birds a worse drink every day.

Our guide to water supply and storage covers how big the tank should be and where to put it, and this article is about keeping that tank clean. The water you drink from the tap at the end of the line tells you little about the tank. The tank is cleaned for the birds, and the birds drink from the bottom of the lines, so the clean has to reach the places they actually drink from.

Scrubbing a plastic, concrete or steel tank without damaging it

The right cleaning method depends on what the tank is made from. Using a wire brush on a galvanised tank or a strong acid on a concrete one will shorten its life, and it can leave a rough surface that holds more slime than before. Check the material first, then choose the brush and the cleaner to suit it.

Whatever the material, scrub from the top of the walls down so the loosened sludge falls to the floor where you can remove it. Pay particular attention to the corners and the join where the wall meets the floor, because that is where the sludge settles and the slime hides. A tank that has been cleaned on the walls but left sludged in the corners is still a dirty tank.

Once the tank is cleaned, the walls and corners are only half of it, so check the parts that surround the tank next.

How often to clean, by where the water comes from

There is no single cleaning date that suits every tank. The water source decides what builds up, and that decides how often you need to look. Use the table as a starting point, then adjust it to what you find when you open the lid. If the sludge at the outlet is more than a finger deep, you are cleaning too late, whatever the calendar says.

Two things change the interval on any farm. A tank in full sun grows algae much faster than one in shade, so a tank on an exposed stand needs more frequent attention. A tank that receives a lot of roof dust, such as one under a dusty track or near a road, also needs more frequent cleaning. Note both on the record sheet so the interval is based on your own site. Tie the tank check to the same day as the drinkers in our weekly cleaning schedule, so the two jobs are never separated by a busy week.

Plan the water gap before you drain a single litre

Birds need water every hour, and in the hot months a flock that goes without for even a short time will suffer. Before you drain the tank, know where the flock will drink while it is empty and refilling. The best plan is a second tank or a set of clean drums that are already full, placed on the house supply line so the birds switch over without a gap.

If you have only one tank, use clean drums filled from a safe supply, and set them up before you start. Mark the drums with the date they were filled, and do not use a drum that has held chemicals or feed. Choose a cooler part of the day for the draining if you can, and keep the drinkers full throughout. If the birds are on any water medicine, ask your vet how to time the clean around the treatment, rather than guessing.

• A second tank, or clean drums already full, on the house line.
• A dated label on each drum, so you know how old the water is.
• The drinkers topped up before the tank valve is closed.
• A check that the flock has drunk normally after the switch.
• The vet's advice on any medicine in the water, written on the record sheet.

When the power fails, the pump fails with it, and a dry tank becomes the emergency. Our generator and backup power guide explains how to keep the supply running through a outage, and it is worth reading before the tank ever needs emptying.

Draining, scrubbing and clearing the outlet

The draining is the easy part, but a few steps make the difference between a clean tank and one that is still full of sludge when you refill it. Follow the order below, and do not skip the outlet, because it is the lowest point and collects the worst of everything.

1. Close the inlet valve so no more water comes in, and note the time on the record sheet.
2. Open the drain or the outlet and let the tank empty fully. Do not leave it half full, because the sludge stays wet and sticks to the walls.
3. Remove the big debris by hand or with a bucket. Wear gloves, and watch for dead insects, lizards and scum.
4. Scrub the walls from the top down with the brush suited to the material, then the floor, then the corners.
5. Clear the outlet strainer and the drain pipe, and flush them with clean water until the water runs clear.
6. Look at the joins, the welds and the seams for cracks, and note any leak on the record sheet before you refill.
7. Rinse the whole tank with clean water until nothing is left on the walls.

Do not refill the tank at once. Let it drain completely after the final rinse, and check the floor for puddles that suggest a leak at the base. A small leak looks like nothing until the tank is half full, and then it is too late.

The screens, the float valve and the overflow: the parts people forget

The walls get the attention, but the small parts around the tank decide whether the water stays clean between cleans. A broken screen or a stuck float can undo a good clean within a day, so inspect these parts every time the tank is open.

• The inlet screen, where water enters the tank. Remove it, clear the mesh of debris and check that no holes have opened.
• The float valve. Clean out grit that makes it stick, because a stuck float overfills, wastes water and lets dirt in around the lid.
• The overflow pipe. Make sure its insect mesh is intact, because standing water in an open overflow is a breeding site for mosquitoes.
• The lid and its gasket. A lid that does not seal lets dust, leaves and rain in, so replace a cracked or hardened gasket.
• The vent screens. Check them for rats and lizards getting in, and for wasps building nests in the openings.

Write any broken part on the record sheet at the time, not in your head. A replacement float or a new mesh is cheap, and it stops a problem from coming back after the next rain.

Flushing the lines from the far end back

The tank is only half the job. The lines carry the water to the birds, and the far ends of those lines are where the water sits longest. Once the tank is refilled, the lines need to be flushed, so that the first water the birds drink is not the stale water that sat in the pipes.

Start at the far end of each line, where the last drinker or the last nipple is, and open the flush point there. Run the water until it comes through clear and smells of nothing. Then move back along the line to the tank, flushing any drip points and low joints on the way. Nipple lines need a particular check: go along the row and watch for nipples that trickle, dribble or block, and clear or replace them before the birds drink.

• Open the flush valve at the last drinker on each line and run until clear.
• Flush any drip points or low joints along the line, including the joints under the house floor.
• Check the nipples for trickles that wet the litter, and clear any that are blocked.
• Check that the drinker heights still suit the birds, because they need raising as the flock grows.

Sanitising at the label strength, and leaving it long enough

Sanitising comes after cleaning, never instead of it. A sanitiser cannot work through a layer of sludge, and chlorine is used up quickly by dirt, so a dirty tank eats the product before it can kill anything. Clean first, then sanitise, and you will use less product for a better result.

The products used for poultry water are normally chlorine-based, and they are sold in several strengths. Read the label and use the dose it gives for the volume of your tank, measured with a clean jug rather than a guess. Mixing more product in the belief that it is safer is the most common mistake, and it can leave a taste the birds will refuse to drink. The solution then needs its full contact time, which is the period the label gives for the water to sit before you rinse or use it. Stopping early means the tank was not properly sanitised.

Chlorine works less well when the water is alkaline or very cloudy, so a clean tank with a stable pH works best. If your water is hard or unusually alkaline, ask your supplier or your vet which product suits it. Wear rubber gloves and eye protection when you handle the concentrate, and keep the product away from children, feed bags and the medicine store.

Rinse, test and refill without poisoning the flock

After the contact time, rinse the tank until the chlorine smell is gone and the water runs clean. Refill with the normal supply, then flush the lines again. Many farms skip the second flush and wonder why the birds drink less in the first hour after a clean. A strong taste or smell in the drinker is almost always a sign the rinse was too short.

If you have a simple test kit for free chlorine, use it on the water at the far end of the line before the birds drink. It tells you the sanitiser is still in the water at a level the birds can tolerate, and that the rinse has removed enough. If you do not have a test kit, the smell and the taste test is your best guide, and your vet can advise on a kit or a check you can rely on.

Write the date, the product, the dose, the contact time and the initials on the record sheet. Afterwards, watch how much the flock drinks over the next two days, using the figures in our broiler water management guide as a yardstick. A clean with no record is a clean you cannot prove, and the next person who cleans the tank will not know what was used.

Scale, rust and the mistakes that come back

Most repeat problems come from a short list of mistakes. They are easy to make and easy to fix once you know them, and most are about the parts of the tank that nobody looks at.

• Cleaning the walls and leaving the sludge in the corners and the outlet.
• Scrubbing a galvanised tank with a wire brush, which strips the zinc and starts the rust.
• Using strong acid on a concrete tank, which etches the surface and holds more dirt later.
• Mixing chlorine with vinegar, acid cleaners or ammonia. Vinegar is sometimes used for scale, but it must be rinsed away completely and never mixed with chlorine.
• Refilling the tank before the walls have dried, which keeps the slime alive in the damp.
• Forgetting the overflow mesh and the vent screens, so insects and lizards move back in within a week.
• Clearing the nipples only at the start of a flock, and not after each clean.

Scale is the one that returns quickest on a hard-water farm. If the nipple pins narrow every few weeks, the problem is in the water and not in the cleaning, and you need to deal with the water source itself. Our guide on water quality for poultry in Ghana covers testing and what to do about hardness and iron.

A year of tank cleaning on a 1,000-litre tank

Here is a worked example for a 1,000-litre tank on a roof-fed supply, standing in partial sun, serving a house of around a thousand birds. The seasons in Ghana change the load a great deal, so the schedule moves with them. Treat the months as rough guides, because the first rains and the start of the harmattan do not arrive on the same day every year.

In this example the tank is cleaned four times a year, with extra cleaning after the first heavy rains because the roof is at its dirtiest then. Heat changes the picture as well, since birds drink far more in the hot months, and our hot weather cooling guide explains why a tank that runs low in the dry spell matters so much. The inspection in between takes ten minutes each time and catches most problems while they are still small.

The tank cleaning checklist

Print this list and fix it to the tank stand, or to the wall beside it, so the person doing the clean has it in front of them. Tick each step, and write the date and initials at the bottom.

1. Note the time, close the inlet and make sure the backup water is in place.
2. Drain the tank fully and remove the big debris.
3. Scrub the walls from the top down, then the floor and the corners, using a brush suited to the material.
4. Clean the inlet screen, the float valve, the overflow mesh and the lid gasket.
5. Check the vent screens and the joins for cracks or leaks.
6. Rinse the tank with clean water until the walls are clear.
7. Sanitise at the label strength, and give the full contact time.
8. Rinse again until the chlorine smell is gone, then refill.
9. Flush every line from the far end back, and check the nipples.
10. Record the date, product, dose, contact time and initials, and set the date of the next inspection.

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