Cost of watering a garden with a hose UK: calculate it

Leave a hose running across the lawn for an hour and the extra charge is hard to picture. The cost of watering a garden with a hose in the UK cannot be reduced to one trustworthy national price. You need your water company's current rate, your hose's actual flow and the time the tap is open.

The 800-litre hourly figure below is the assumption in the CCW water-meter calculator, not a reading from your tap. We have not measured hose flow in a lab. A qualifying purchase through our links can earn us a commission at no extra cost to you.

In short

One cubic metre is 1,000 litres. Divide the litres used by 1,000 and multiply by the charge per cubic metre on your bill. CCW uses 800 litres per hour as a calculator assumption, but published estimates differ and your hose may deliver more or less. Meter a normal session before you decide what summer watering costs.

Calculate your hosepipe cost

Start with the unit rate on your latest bill or your company's charging schedule, usually pounds or pence per cubic metre. Do not divide the total bill by consumption until you see what else is inside it. Standing charges, sewerage and other fixed items can distort the result.

Litres used divided by 1,000, times the water rate per cubic metre, is the water-only cost. A session of 400 litres at £2.10 per cubic metre is 0.4 cubic metres, so 0.4 × £2.10, or £0.84. Those figures show the arithmetic. They are not a typical UK tariff. Use your measured volume and the rate your supplier prints.

If that session costs £0.84 and you repeat it three times in a week, the water-only total is £2.52. Stretching one hourly estimate across a whole summer is weaker, because weather, planting and session length change. Record a few dry-week sessions instead.

Turn pence per litre into a quick check

Divide a cubic-metre rate by 1,000 for the price per litre. A £2.10 rate is £0.0021 per litre, or 0.21 pence. Keep cubic metres as the main sum. The standing charge normally stays the same whether you water or not, so leave it out of one hose session. Sewerage may be calculated from a proportion of metered use, so give it its own line.

Find your real hosepipe flow rate

CCW's calculator assumes an average hosepipe, with or without a gun, uses 800 litres in an hour. Another UK garden-watering calculator uses 1,000 litres per hour. Neither number is your tap. Flow changes with mains pressure, how far the tap is open, hose length and bore, kinks, connectors, spray pattern and other demand in the house.

Measure the setting you actually use. Time how many seconds a container of known capacity takes to fill. Litres per minute is container litres divided by seconds, times 60. Multiply by 60 again for litres per hour. A 10-litre container that fills in 60 seconds is 10 litres per minute, or 600 litres per hour. Repeat the test twice. If the results jump, check that the tap and the spray setting stayed the same. Do not time an overflowing bucket, or measure on a jet when you normally use a shower pattern.

Measure time as well as flow

Duration is what reaches the bill. At 600 litres per hour, 15 minutes of continuous flow is about 150 litres. If you release a shut-off while you move, time only the periods when water flows, or read the meter before and after. Pick a short window when no toilet, washing machine or indoor tap is running, or those litres will sit inside the reading.

Separate water and sewerage charges

Garden water often does not return to the sewer, but that does not automatically strip sewerage from every metered litre. Many bills estimate wastewater as a proportion of water supplied. Read the water and wastewater lines separately, including any return-to-sewer percentage, and use your supplier's charging scheme. If two companies are involved, you may need both documents.

For an upper figure, apply the water charge and any variable sewerage charge as the bill describes. For a water-only figure, use only the supply rate and label it that way. The gap matters when you compare a mains hose with stored rainwater in a water butt or mains hose. Some suppliers may adjust a bill, or explain a separate meter, where a large volume misses the sewer. Ask in writing before you subtract sewerage yourself. A garden is not a national exemption.

Reduce cost without guessing

The dependable saving is fewer unnecessary litres, not a percentage printed beside a nozzle. A trigger shut-off stops flow while you walk between plants, and it saves water only when you use it. Water the soil around the roots, and skip a session after meaningful rain. Ten litres costs the same from a can or a hose. The can makes the quantity visible for a few pots. A hose is usually faster on a large border.

Repair drips at the tap connector, the joint and the gun before a long session. A leak can run whenever the tap is open, including while the trigger is closed. Replace a washer or connector when that is the fault, and replace a hose that will not stay watertight, as set out in when to replace a split hose.

The spray hose comparison sets shut-off controls and patterns side by side. The top pick is the Onarway metal spray gun, about £15.74, with 4.7 from 262 amazon.co.uk reviews, which we score at 9.4. The listing states ten patterns, a rear flow knob and a trigger lock. It does not state a measured saving for your property. Test the setting you will use, and check whether a gentler flow makes the job take longer.

Use a simple watering log

For one dry week, note the meter or the measured flow, the minutes and the areas watered, plus rainfall and whether the soil was already damp. If a trigger gun cuts time between plants, the volume should fall for a comparable job. If a lower-flow pattern doubles the duration, the saving may shrink. Volume is what the meter sees.

Unmetered bills and hosepipe bans

On an unmetered bill, hose use does not usually add a per-litre charge. The formula in this guide will not reproduce that bill. You can still measure a session, both to see the demand and to prepare if you later move to a meter. An unmetered tariff is not a promise of unlimited use.

Water companies can introduce temporary use bans. A ban concerns what you may do, not whether you are metered, and it does not create a special hosepipe price. If a use is prohibited, paying the metered rate does not make it allowed. Check your supplier's current notice. What you can still water in a hosepipe ban is a separate question from the cost.

Articles that put a hose at about £1.50 an hour are using a 2017 figure. It is not a 2026 national price. Company rates differ, and an hour at 500 litres is not an hour at 1,000 litres. Your bill and a measurement settle both.