Water for bees, and keeping them out of the neighbour’s pool

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Bees do not store water

There is no water in the hive the way there is honey in the hive. Foragers fetch it as it is needed and pass it straight to other bees, which is why a colony can be in trouble within a day of losing its supply. 1

A water carrier fills her crop with 30 to 58 microlitres and flies home. That is a very small amount of water per trip, which tells you how many trips a hot day costs.

They will go up to 2 km for it, but no further than they can afford, because a bee carrying water home cannot carry fuel in the same crop.

What they use it for

• Drinking.
• Softening stored honey, which is why they need it in winter and early spring as well as in summer. 1
• Cooling the nest. In hot weather they spread water over the combs in a thin film and fan it, and the evaporation carries the heat away. The NBU calls this essential in hot weather.

The NBU is explicit that bees need water throughout the year, not just in summer.

How much

There is no single honest figure, and you should be suspicious of anyone who gives you one. Published measurements vary a great deal with colony size, brood, weather and how exposed the hive is. Across the studies we could find, a colony might take a couple of hundred millilitres on a mild day and well over a litre a day in real heat, with a strong colony’s annual use running into tens of litres.

Treat that as a range rather than a target. The useful version for a beekeeper is simpler: on a hot day a colony needs a lot more water than you would guess, and it needs it close by.

Give them their own supply

The NBU’s first piece of advice is to site an apiary near a suitable water source in the first place. 1 Where there is not one, provide it, and provide it before hot weather rather than during it. Bees learn a water source and keep going back to it, so the time to establish yours is early.

Things that work, all from the same guideline:

• A bowl of water with pebbles in it, so there is something to stand on.
• An old animal feed station filled with water.
• An entrance feeder adapted for water, though a communal point a little away from the hives is often better.
• A water butt with floats on the surface, so nothing drowns.

The detail that makes the difference is that bees would rather draw moisture from a wet surface than from open water. Wet soil, sand or brick suits them better than a clean dish.

Three more preferences worth knowing, all from the NBU: they like a dark surface, because it is warmer in early spring; they prefer water warmer than 18 °C; and they are drawn to water with a low concentration of salts. The guideline suggests adding a little salt when you first put a supply out, to get them started on it.

Drowning

Anything with an open water surface and no landing place will kill bees steadily and quietly. Pebbles, gravel, corks, twigs, straw or a floating board all solve it. Top it up before it dries out, because a supply that runs dry sends them looking somewhere else, and somewhere else is usually a neighbour.

The neighbour problem

This is the one that causes trouble. The NBU says plainly that bees can be a nuisance by taking water from swimming pools and garden ponds, especially in dry periods, and that a suitable source closer to the apiary may help prevent it. 1

Note the order of events. Bees do not choose a pool because it is a pool. They choose the nearest reliable water. Once a few hundred foragers have learned it, they are extremely hard to move, and the conversation with the neighbour is much harder than the one you could have had in April.

So the practical answer is to get in first:

• Put your own supply out early in the season, before the pool cover comes off.
• Make it closer than the thing you are competing with, and keep it topped up.
• If they are already on a neighbour’s water, put your supply right next to it, get them using it, then move it a little at a time.

Do not put anything in water that is not yours to treat. If a neighbour asks you to deter bees from their pond, the answer is your own better water source, not additives in theirs.

Drought and hosepipe bans

Dry summers are exactly when the neighbour problem starts, because the puddles and ditches the bees were using disappear.

On restrictions, the safe and simple answer is a water butt. Rainwater you have collected is yours and is not affected by a hosepipe ban, it is free, and bees are perfectly happy with it. A butt with floats on the surface solves the supply problem and the rules problem at once.

Restrictions differ between water companies and change from year to year, so check your own supplier’s current rules rather than relying on what a beekeeper told you last summer. We are not going to tell you what your water company allows.

Water in the hive

Normally you do not feed water inside a hive. There is one exception in the guideline: when bees are shut in for a long move, or confined during crop spraying in hot conditions, they need water and cannot go for it. A frame feeder half filled with water, with straw or floats in it to stop them drowning, goes beside the brood chamber. Regular light spraying through a mesh travelling screen does the same job. 1

Do not confuse this with feeding. Syrup is a different job with different rules: Making sugar syrup.

The short version

• Bees store no water. They fetch it daily, all year.
• A crop load is 30 to 58 microlitres, and they will fly up to 2 km for it.
• Put a supply out early, before hot weather and before the pool cover comes off.
• A wet surface beats open water. Dark, above 18 °C, slightly salty to start.
• Always give them something to stand on.
• A water butt with floats answers both the drought and the hosepipe question.
• Never treat water that belongs to someone else.