For light garden watering a water butt with a capacity of up to 300 litres will suffice.  If space is tight you can use a slimline butt with a 100 litre capacity but you are likely to run out of water in extended dry periods.

 

We would not recommend use of pumps or pressure washers with butts as they are likely to use the water too quickly.

 

If you want to water larger areas of garden with a hose or sprinkler the minimum size of storage you should consider is a tank of at least 700 litres capacity.

 

Choose your method of water distribution carefully.  Some submersible water butt pumps have a flow rate of 1200 litres per hour and will exhaust your supply rapidly.  Also, some tanks only have 100mm openings and most submersible pumps require an opening of at least 160mm.

 

As an alternative you should consider a pressure washer.  They will draw the water from the tank and the small domestic units operate at a flow rate of about 330 litres per hour.  A pressure washer can be used for garden watering when the pressure nozzle is not fitted. 

 

Please note - we do recommend that the rainwater is filtered if a pressure washer is to be used, either when entering the tank (using one of our diverters with an integral filter) or when the pressure washer draws the water out of the tank.  Karcher do offer a suction hose extension with filter in two different lengths.

 

The best solution for car cleaning with rainwater is one of our 700 litre tanks connected to a pressure washer.  This will give you up to 2 hours continuous use per tank of water. 

 

Please see filter notes above when using a pressure washer.

 

A 100 litre or 250 litre slimline water butt is available for very tight locations.  You can also consider siting a tank further away and using a hose and/or pump system to move rainwater into larger storage.

 

We can supply larger above ground tanks of between 1300 litre and 10,000 litre capacity for the larger domestic and small commercial application.  A range of underground rainwater storage systems of up to 4600 litres is also available.

 

In the domestic situation tanks and butts can be linked together to form larger storage capacities using our linking kit.

 

The amount of rainwater landing on your roof will depend where you live in the UK!  Assuming you collect 60% of the rain falling, 1 m2 of roof should typically deliver 480 litres of rainwater per year in the Midlands, and 360 litres even in the dryest areas of the country.  To capture that you will need to introduce a rainwater diverter into your guttering downpipe.  The diverter should be placed level with the highest water level in the tank and higher than the pipe inlet into to the tank.  If this is achieved, when the tank is full the rainwater in the downpipe will be diverted past and into the drainage system.

 

Our universal diverter will fit 65mm square and 68mm round downpipes.  Most guttering manufacturers will also supply a diverter specifically designed for their products.  Ask your local Builders Merchant for details.

 

Diverters are also available complete with filtering systems.

 

Butts and tanks should ideally be sited close to your rainwater downpipe.  Butts should be raised off the ground to allow watering cans to be filled from the bottom outlet.  Tanks should be placed on level ground and fully supported across their base, ideally on concrete or similar slabs.

 

If you have young children that could gain access, butts and tanks with larger openings must have a lockable lid.

 

When temperatures fall below freezing you should empty small water butts and tanks to prevent damage.  Also please remember that in low temperatures plastic materials become brittle and are much more susceptible to impact damage.