100 litre water butt: the checks before you buy

Updated: 22 October 2026

A search for a 100 litre water butt still returns larger kits, because the title says rain and the capacity line says something else.

A search for a 100 litre water butt still returns larger kits, because the title says rain and the capacity line says something else. This page is the checks: what 100 litres will water, whether the box is a tank or a kit, how deep a slimline is, and which pipes a diverter fits. The 100 litre water butt comparison holds the five amazon.co.uk listings, from £29.99 to £49.88 on 19 October 2026. Peter F. used those listings plus the RHS, RoSPA, Ofwat and Waterwise. There was no lab fill. A purchase through those links may earn us a commission at no extra cost to you.

Our top picks

Badge	Product	Form	Stand in the box	Listed size	Note	Price	Offer
Best overall	Bowers Bargains Bowers Bargains (100l-slim-wb)	Slimline, rigid	Title claim	36 × 32 × 96 cm	7.5	about £39.99	View offer
	Plant!T Plant!T (GN334)	Slimline, rigid	No	10 mm row is not usable	8.9	about £33.89	View offer
Alternative	Vision4ever Vision4ever (VD-775)	Slimline, rigid	Title claim	41 × 92 × 41 cm	3.2	about £29.99	View offer

Best overall

Bowers Bargains Bowers Bargains (100l-slim-wb)

7.5/10about £39.99

View offer

Rank 2

Plant!T Plant!T (GN334)

8.9/10about £33.89

View offer

Alternative

Vision4ever Vision4ever (VD-775)

3.2/10about £29.99

View offer

On this page

1.What a 100 litre water butt is for
2.Capacity, footprint and kit contents
3.Downpipe, stand and lid
4.When to choose a larger butt instead

What a 100 litre water butt is for

A 100 litre water butt is a rain store for pots, a greenhouse bench, a shed roof, or a few tubs. A full tank is about 100 kg. You site it once, on a firm level base. Education Nature Park guidance puts a slimline of this size in tight spots and says it will not last a long dry spell if you dip in often. Overflow has to return down the pipe to the drain. Stored rain is for the garden. The Environment Agency's guide says harvested rain is not drinking water unless treated to a potable standard, and it is not for washing food. RoSPA says cover or fence off water butts, because a young child can drown in very little water. A clip lid is a cover, not a certified child lock.

Capacity, footprint and kit contents

Read the capacity on the specification line, not the search title. Twenty-six gallons is about 98 litres. If the title says 100 litres and another field says 26 gallons, notice both. Rigid slimlines here that print a real size sit about 32 to 41 cm deep and roughly 92 to 96 cm tall before a stand. Bowers Bargains prints 36 × 32 × 96 cm. Vision4ever prints 41 × 92 × 41 cm. The Plant!T GN334 also prints 10 × 10 × 10 mm and 1 kg. Ignore those two figures. Kit in a title is not an included-components line. On the GN334 that line is the butt only, at £33.89. The Bowers title claims a stand and a downpipe kit at £39.99, and one verified review says the parcel was the butt and a tap. Vision4ever's title claims a hose, tap and stand at £29.99, with no separate parts list and no review line.

Testsieger

Bowers Bargains Bowers Bargains (100l-slim-wb)

7.5/10about £39.99

View offer

Downpipe, stand and lid

A diverter sends roof water into the tank and, when the tank is full, lets the rest continue down the pipe. Strata's 100 litre slimline set cites 68 mm round or 65 mm square plastic downpipes. Measure yours before you order the fitting. Cast iron, or a size that is not on the card, is a stop. A shared stack is the same stop. Without a stand the outlet sits too low for a watering can. Waterwise says empty the butt when freezing is a risk, and put it on a base that can carry the full weight. If the pipe is the right plastic and you know whether the stand is in the box, the sequence is on the how to install a water butt page.

When to choose a larger butt instead

Stay at 100 litres when space is the constraint and the job is a can. Move up when you are watering a family garden through a dry fortnight. Garden-review's 2026 notes put about 100 litres with a courtyard or greenhouse, and 200 to 250 litres with a family plot. That is a rule of thumb. The RHS describes linking butts when one wide barrel will not fit. The slimline or collapsible water butt page keeps that split. Who should open which listing first is the best 100 litre water butt page. A 100 litre butt does not change a hosepipe ban. It only holds rain you have already caught.

Common questions

Is 100 litres enough for a small UK garden?

It is enough for cans on pots, a greenhouse, or a shed-side tub. It is not enough for a sprinkler or a long dry spell if you water every day. Ofwat's sprinkler range is 500 to 1,000 litres an hour, so the tank would empty almost at once. A family vegetable plot usually wants more storage, or a second butt linked to the first.

What should be in the box?

A tank, a tap you can seal, and a lid. A stand and a diverter make it usable on day one, and they are often separate. On the Plant!T GN334 the included-components line is the butt only. A title that says kit still needs a parts list: one buyer in this set received the butt and a tap and nothing else.

How deep is a slimline 100 litre butt?

Where this set prints a credible size, rigid tanks are about 32 to 41 cm deep and about 92 to 96 cm tall before a stand. Bowers lists 36 × 32 × 96 cm. Vision4ever lists 41 × 92 × 41 cm. Ignore the 10 × 10 × 10 mm row on the GN334. If the side return is under 40 cm, measure the passage and the stand's footprint before you order.

Do I need a stand?

You need one if a watering can must slide under the tap. Without a stand the outlet sits too low, which buyers of the GN334 solve by purchasing a stand later. It has to stay level under about 100 kg. If the title includes a stand, confirm it is in the parcel before you cut the downpipe.

Will a diverter fit my downpipe?

Fittings cited for this size are for 68 mm round or 65 mm square plastic pipe. Measure yours. Cast iron, an odd diameter, or a shared stack is a reason to stop. The diverter should send overflow back down the pipe to the drain, not onto the wall.

Water butt and a hosepipe ban