Water reuse

Every time you collect rainwater in water butts and containers to reuse in the garden, you’re effectively rainwater harvesting.

If you have a mains water backup to your rainwater system you’ll need to let us know.

Rainwater harvesting systems

If collected and stored correctly, with minimal treatment, rainwater can be used for garden watering, toilet flushing and in washing machines – potentially cutting household water usage by up to 50%.


Realistically, most roof areas are too small to collect enough rainwater to meet households’ needs, but if you’re keen to invest in equipment, do some research first. The British Standard BS EN 16941-1:2018 Rainwater harvesting systems Code of Practice can tell you what standards you need to meet.

Your rainwater shouldn’t be used for drinking, bathing, dishwashing, filling swimming/paddling pools or anything requiring a high water quality - it could contain harmful bacteria and make you ill.


If you do invest in a rainwater harvesting system (which shouldn’t be confused with water butt collection), below are some tips on how to look after it and your drinking water.

Looking after your system

Check the system from time to time. Does the water in the tank look murky or is it starting to smell? When the collection filters become blocked or broken, or you have a poorly-fitted inspection cover, they can allow debris from your roof and elsewhere to enter the tank. When this breaks down, it causes a murky look or musty smell. If you cannot identify the problem, contact the manufacturer to find a professional to inspect and clean it.

An inside blocked filter or pump failure can stop rainwater flowing to your toilets and garden taps, causing your toilet water to look dirty after flushing or stopping it filling. If your cistern’s not filling, keep your toilets working by using a bucket of water to flush them or fill the cistern so you can flush normally.

Clear gutters. Removing leaves, moss and other debris will keep the rainwater cleaner.

Ensure the mains water backup doesn’t splash in from the top of the tank. It’ll stir up sediment at the bottom. If it causes a problem, contact the manufacturer.

Check your rainwater and main water connections. If your drinking water has a funny taste or smell or the water in your washing machine isn’t cleaning your clothes, you may have cross-connected the rainwater system to your mains plumbing, mixing both supplies together. If you find this, contact us immediately.

Label the garden tap and pipes carrying rainwater into your house. If your drinking water has a funny taste or smell you may be drinking from the wrong supply. Labelling reminds everyone the water isn’t safe to drink.

Don’t remove the pipe and system labelling. It’s there to keep you and your family safe and let your plumber or other people working in your home know your plumbing has a rainwater harvesting system.

Service all filters (or the UV disinfection unit if you have one) at the recommended times. Prevention is better than a breakdown.

Check the mains supply. If you’ve no rainwater to draw upon, it’ll give you peace of mind your backup supply’s working. 

If your system breaks down don’t be tempted to connect your toilet supply to the mains water system. It’s too much of a risk to your drinking water. Call an approved plumber and say you have a rainwater system.

If you have any problems with your rainwater harvesting system, contact the manufacturer or an approved water reuse plumber.

Looking after your drinking water

If you have a water meter, check and read it regularly. If you notice an increase in the amount of water you record, you could be using the mains backup more, especially if there’s been no rain. While this is normal, it’s worth checking the increase isn’t due to a problem with your rainwater system.

Check your normal plumbing system.  Ensure your rainwater system isn’t directly connected to your drinking water.

Ensure any mains water backup goes through a properly installed category 5 air gap.

If you have a rainwater harvesting system and your drinking water tastes odd, call us immediately on 03457 145 145 so we can investigate. Lines are open 24/7.

Greywater reuse

If you carry a bowl of bathwater outside to water the plants then you’re already recycling some of your greywater. This used water from baths, showers and sinks can be relatively clean – depending on how much soap, shampoo and shower gel you use – so collect and reuse where possible.

The British Standard BS8525-1:2010 (Greywater Systems Code of Practice) advises that providing it’s treated properly, greywater can be used for toilet flushing, garden use and washing machines. It shouldn’t be used for bathing, dishwashing or anything requiring higher water quality, because of potential health risks.

Everyone can save water and money. Fitting water efficient devices and learning how to save drops.

Business customers

If we do not supply your water, we are still required by water regulations to inspect your property. Contact your supplier for more information on how to maintain your rainwater system.

Our rainwater harvesting leaflet provides information on how to keep your system healthy.