Watering the garden with treated tap water is expensive in dry summers and adds to demand on supplies just when they are under most pressure.
Rainwater is free, and many plants prefer it.
How it works
A water butt connects to a downpipe from the roof, shed, or greenhouse with a diverter kit. When the butt is full, the diverter sends overflow back down the drain. A tap near the bottom lets you fill a watering can.
Choosing a water butt
- Size: larger butts store more for dry spells; link several together if space allows
- Lid: a secure lid keeps out children, animals, mosquitoes, and debris
- Stand: raising the butt makes it easier to fit a watering can under the tap
- Material: opaque, dark plastic reduces algae growth
Using rainwater
Rainwater is ideal for ornamental plants, lawns, and acid-loving plants like blueberries and camellias, which dislike hard tap water. For seedlings, many gardeners use tap water to reduce the small risk of fungal disease from stored water.
Maintenance
Clean the butt out once a year, ideally in winter when it is least needed, and check the diverter filter for leaves. In freezing climates, disconnect or drain the butt so ice does not crack it.
This is general sustainability information. Recycling, composting, and disposal rules vary by municipality — check local guidance. Cost and energy savings are estimates and depend on your home and usage.