After the summer the UK has just had, September rain is a relief rather than an inconvenience. Reservoirs start to recover, gardens revive, and the restrictions that shaped the last two months begin to lift.

It is also the moment most households stop thinking about water entirely, which is precisely the wrong time to stop. Every millimetre that falls on your roof between now and March is free water, and unless you have somewhere to put it, all of it goes straight into the drain.

Why Autumn Beats Spring

Most people buy a water butt in May, when the garden is dry and they suddenly want one. That is far too late. An empty butt installed in spring has to wait for rain that may not come in a quantity that matters until autumn.

Installed now, the same butt fills through the wettest half of the year and sits full and ready when the next dry spell arrives. Autumn is also simply an easier time to do the work: the ground is soft enough to level a base, and you are not competing with peak-season stock shortages.

What Stored Rainwater Is Actually For

This is the part people underestimate. Temporary Use Bans restrict the use of a mains-fed hosepipe. Water you have collected yourself is your own supply, so a stored butt keeps your garden, your pots and your car washing going through a restriction that would otherwise stop them dead.

Beyond the garden, rainwater is perfectly suited to any non-potable demand in the house. The single biggest one is toilet flushing, which accounts for a substantial share of household consumption and requires no drinking-quality water whatsoever. Our guide on utilising rainwater for toilet flushing explains how plumbed systems work and what they realistically save.

Setting Up Properly

• Fit a diverter, not a bucket. A downpipe diverter kit routes rain into the butt and sends the overflow back into the drain automatically once it is full.
• Raise it up. A butt sitting on blocks or a purpose-made stand gives you the head of pressure needed to fill a watering can from the tap.
• Keep it covered and dark. A sealed lid keeps out leaves, algae and mosquitoes, and keeps children and wildlife safely out too.
• Watch where the overflow goes. This one matters more than people think. Water discharging against a wall or into already saturated ground over winter is a genuine problem, and our guide on how soakaways protect your property's foundation covers how to deal with it properly.

For planting and design guidance that works with a rain-fed rather than mains-fed garden, the Royal Horticultural Society (RHS) Sustainable Gardening Guide is an excellent free resource.

Know Your Baseline First

Storage is most useful when you know which parts of your consumption it can actually offset. Understanding what your household uses, and where, tells you whether a single butt is enough or whether a larger system is worth the investment.

Curious where your water actually goes? Use our online calculator to estimate your household usage and spot the savings worth chasing.