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Water level around corners

Updated: 22 October 2026

The second point is behind a wall, around a bay, or down posts you cannot see in one look. A straight level stops, and a laser beam stops with it. A water level around corners carries one height along the path the hose can walk, and any slope is a sum you apply afterwards. This page assumes you already have a hose. Hose or laser is on the [water level vs laser level](/hub/measuring-and-marking-tools/hose-level/sub/hose-level-vs-laser) page. The listings are in our [hose level comparison](/hub/measuring-and-marking-tools/hose-level). Peter F. used UK guides, Approved Document C, and amazon.co.uk reviews gathered on 20 October 2026. There is no lab test of these hoses. A qualifying purchase can earn us a commission at no extra cost to you.

The second point is behind a wall, around a bay, or down posts you cannot see in one look. A straight level stops, and a laser beam stops with it.

Our top picks

as-Schwabe as-Schwabe 10 m PVC hose

Best overall

as-Schwabe as-Schwabe 10 m PVC hose
8.4/10about £10.56
View offer
Cellfast Cellfast 20 m (22-101)

Rank 2

Cellfast Cellfast 20 m (22-101)
9.2/10about £14.01
View offer
Cellfast Cellfast 25 m hose level

Alternative

Cellfast Cellfast 25 m hose level
7.6/10about £17.12
View offer
On this page
  1. 1.One datum and a hose that is not pulled tight
  2. 2.Fence posts and deck posts
  3. 3.A gutter fall is level first, then a drop
  4. 4.A damp-proof course height is a mark, not a sign-off

One datum and a hose that is not pulled tight

Pick one reference mark and keep it. That is the datum. Walk the hose the long way around the obstacle, and leave a gentle curve at the far point. A tube pulled tight can kink, and the two ends stop reading as one level. DIY Doctor’s fence method is two people and a pause until the water is still. Path length beats the straight line. A 10 m hose, the as-Schwabe at £10.56 or the Faithfull at £21.99, covers a short fascia if the route is not much longer than the tube. DIY Doctor suggests about 15–21 m for posts around obstacles. The 25 m Cellfast set, at £17.12, is the long reach when a path around the house would stretch 20 m. A tight hose at the far post means the route is longer than the tube.

Fence posts and deck posts

Set the first post, then copy it. DIY Doctor waits at that post and marks the next from the same part of the meniscus. Both people use the high point of the curve, or both use the low point. One Cellfast review tied a tube to a stake. That can work if the stake cannot slip, and you still check back at the first post. If the next post would pull the hose straight, mark an intermediate post and start the next leg with slack. A run that still finishes tight at 25 m is past this set. The fill, the meniscus, and the caps are on how to use a water level.
as-Schwabe as-Schwabe 10 m PVC hose

Testsieger

as-Schwabe as-Schwabe 10 m PVC hose
8.4/10about £10.56
View offer

A gutter fall is level first, then a drop

The hose finds level. It does not slope the gutter. One UK review, shared by the two as-Schwabe listings, marked five level points on a fascia and then worked out the fall. Put a level line on the fascia, measure the run, and drop the outlet by a figure from a gutter guide. JDP uses about 1 in 350, about 3 mm per metre, and asks that the outlet stay within about 50 mm of the roof edge. This search did not find 1 in 350 as a Building Regulations number, so it stays a supplier guide. A 4 m run at about 3 mm per metre is about 12 mm of drop. You mark that down from the level line. You do not tip the hose and expect the water to hold a slope.

A damp-proof course height is a mark, not a sign-off

You can transfer a height. You cannot sign a wall off with a hose. Approved Document C, in the 2013 edition on GOV.UK, says at paragraph 5.5 that an external-wall damp-proof course should be at least 150 mm above adjoining ground unless the design protects the wall, and that it should be continuous with any floor damp-proof membrane. PD 6697 and BS 5628-3 are about the masonry. A hose can carry the 150 mm mark from a reference you trust. It does not choose the material. That 150 mm line is England’s Approved Document. A job in Scotland needs the Scottish guidance, which this page has not checked. Stop when the course is missing or bridged, or when a drain has to meet a regulated fall.

Common questions

How do I get a level mark into the next room?
Keep the datum in the first room, walk the hose through the doorway with slack, and mark the far wall from the same part of the meniscus once the water is still. Both ends stay open for the reading. A beam cannot turn the corner. The water can, if the hose lies in a curve and is free of bubbles.
How do I set fence posts to one height when I cannot see them all?
Set the first post, then copy that waterline to each post you can reach without pulling the hose tight. If a corner makes the hose tight, mark an intermediate post and start the next leg from there. A 15–20 m hose covers a modest garden. The 25 m Cellfast is the long option at £17.12.
Can the hose set a gutter fall by itself?
It can mark level on the fascia. The fall is a drop you measure from that line. JDP and Wickes describe about 1 in 350, about 3 mm per metre, checked with a string and a spirit level. That ratio is their guide, not a Building Regulations figure found for this page.
Can I use it to transfer a damp-proof course height?
You can transfer a mark, including the 150 mm above adjoining ground in Approved Document C for England, unless the design protects the wall. The hose does not choose the material, and PD 6697 and BS 5628-3 are about the masonry. Scotland was not checked against that England figure. A missing or bridged course needs a competent person.
When should I stop and call someone?
Stop for a regulated drain, the setting out of a building, or a damp-proof course that is missing or bridged. A hose can repeat a height around a corner. It cannot design the fall or certify the wall. An optical level, used against a drawing, is the next step for a plot.

Related pages

Water level hose buying guide

Hose level

Best water level hose: top pick and who should skip

How to use a water level: bubbles, open ends, marks

Water level vs laser level when the far mark is hidden

Sources

Public UK sources from the research digest, plus the amazon.co.uk listings compared on this page. Listings captured 20 October 2026.

  1. DIY Doctor, water level (retrieved 20 October 2026)
  2. GOV.UK, Approved Document C (retrieved 20 October 2026)
  3. Consumer Rights Act 2015, section 9 (retrieved 20 October 2026)
  4. BuildWiz, water level (retrieved 20 October 2026)
  5. B&Q, water levels (retrieved 20 October 2026)
  6. York Survey, 25 m graduated water level kit (retrieved 20 October 2026)
  7. Selco, water level (retrieved 20 October 2026)
  8. Pico Hydro manual, chapters 7–8 (retrieved 20 October 2026)