Get $4,000 accuracy — for $25by Joe
For about the same cost as putting a half tank of gas in a small
pickup, you can build a leveling device that is as accurate and
versatile as the most expensive rotating laser level or optical
transit on the market. In fact, this low-cost level can do a few
tricks that neither of those top-of-the-line tools can do at any
price — "seeing through" or leveling around obstructions, for
instance. What's more, it's quick to set up, can be made from items
at any hardware store, requires no calibration, is nearly
indestructible, and is so easy to use that you'll be able to train
every greenhorn carpenter on your crew how to operate it in about
I'm referring to the water level, of course — an ancient tool
that works on the principle that water always seeks its own level.
Fill a long, flexible tube with liquid, and the liquid at both ends
will be at the same level whether you're holding them together or
spreading them a hundred feet apart (Figure 1). Once you learn to
trust that idea, and take some basic precautions to maintain the
accuracy of your water level, you'll be amazed at what you can do
with such a simple tool. All you need to do is hold or clamp one
end of the tube at the starting elevation and the other end of the
tube at the point where you'd like to transfer that
Figure 1. As long as the rules of physics
don't change, water levels will work. It doesn't matter if the two
ends of the tubing are right next to each other, or a hundred feet
away. Water seeking its own level provides level benchmarks for the
deck builder's convenience.
Building a Water Level
To make a basic water level, you need only four items: a length of
clear flexible tubing, a few spring clamps, water or other fluid,
and a couple of one-gallon plastic jugs (to help with filling and
Tubing. This can be almost any length you like; I
find 100 to 150 feet is a manageable length that will serve most
applications. A variety of diameters will work as well, but I've
settled on 5/16-inch or 3/8-inch inside diameter for lengths up to
150 feet. (The level shown in this article is 125 feet of 5/16-inch
vinyl tubing.) Most "big box" supply stores stock clear vinyl
tubing in bulk rolls and will cut you whatever you want. I paid
around 15¢ per linear foot for mine (less than $20 total with
The longer the length, the larger the diameter should be (to avoid
the problems mentioned in the "Pitfalls and Gotchas" section on
page 84), but don't sweat it if you can't find exactly what you
want. I've used everything from 1/4-inch ice-maker tubing to
5/8-inch or larger (garden-hose size) with good results.
Clamps. Remember how putting your thumb over the
end of a straw will hold the liquid in even if the other end is
open? Same with a water level — as long as you can totally
shut off one end, you can move the tubing around from place to
place without losing any liquid. I like to use spring clamps, which
I buy large enough to clip onto a piece of 2-by material. That way,
they can serve as a second set of hands if you're working alone.
Buy one pair to cap off your tubing and a couple of extras to help
you hang the level as you're using it.
Fluid. Plain old water will work in a pinch, but I
prefer windshield-washer antifreeze. It's easier to see and less
prone to taking on air bubbles; it comes in its own handy gallon
jug for filling; and — if you're unlucky enough to have to
work outside in the winter north of the Mason-Dixon line — it
won't freeze in your truck overnight.
Fill 'Er Up
Before you can use your water level for the first time, you need to
fill it with fluid. I do this by siphoning. I set a full jug of
windshield-washer antifreeze on the roof of my truck, and using one
of the spring clamps, secure the tubing to the gallon jug so it
can't fall out (Figure 2). The rest of the tubing starts out as a
coil on the ground.
Figure 2. By placing the source of the liquid
up high, you only need to start the siphon. Gravity will take over
and fill 150 feet of tubing in short order. Windshield-washer fluid
works better than water because its color makes it easier to see,
and it doesn't freeze.
A quick drag on the lower end of the tube will start the filling
process. Sucking just enough liquid out of the jug to fill the tube
to a little below the level of its upper end is all that's needed
to start the flow. After that, gravity takes over. Never wait to
get a mouthful — the antifreeze in windshield-washer fluid is
Once the tubing starts to fill, secure the other end in your empty
gallon jug on the ground. As soon as the tubing is full —
with a full stream flowing into the second jug — clamp off
the upper end of the tubing to stop the flow.
To refill the level (to eliminate air bubbles or to add more
liquid), you can use the same siphoning technique, but there's no
need to risk a mouthful of antifreeze. I use the roof of my truck
as before, but this time I start with everything on the roof
— instead of having the rest of the tubing on the ground.
Then I remove both clamps and toss the coil of liquid-filled tubing
from roof level to the ground. Gravity will do its thing and start
the new liquid flowing.
With a little practice, you can refill your water level in a couple
of minutes every time you roll it out of your truck. As soon as the
liquid is flowing, put the lower end of the tubing into your empty
overflow jug, and allow the new liquid to completely replace the
fluid in the tubing, displacing any air bubbles along the
Using the Water Level
For most water-leveling chores, the setup is the same: First, fill
your level so you have from a few inches to a foot or so of empty
space at each end. You'll need this for adjustment purposes.
Next, find a way to support both ends of the tubing so they hang
vertically but can slide up and down. (This is where extra spring
clamps and a little creativity will come in handy.) A couple of
nails placed on either side of the tubing — just enough to
catch it, but not tight enough to pinch the tubing, will do the
trick. You can also tuck the tubing behind a vinyl-siding
J-channel, or clip it to a grade stake or concrete form using a
couple of spring clips (Figure 3).
Figure 3. There must be 50 ways to hold your
level, but nails and clamps will do the trick. The key is to hold
the end in a way that permits it to be moved for fine-tuning, but
that doesn't close off the tube.
Once both ends are supported at roughly the right level, unclip
both ends and let the liquid find its own level. From here, you can
measure up or down from a reference mark and transfer that
measurement to the other end of whatever you're leveling. However,
I prefer to slide the tubing up or down until the meniscus lines up
with whatever I'm trying to level, and then I head over to the
other end and make my mark (Figure 4). The latter approach is
foolproof and eliminates measuring mistakes: My favorite screw-up
is holding my tape on the one-inch mark at one end but forgetting
to do that on the other.
Figure 4. Marking directly from the fluid
level is the most accurate approach to using a water level.
However, you can also clamp the first end at a convenient height
and measure up or down to the target level. Then, on the end whose
level you're setting, just measure the same distance and
Pitfalls and Gotchas
Using a water level is very straightforward, but accuracy requires
an uninterrupted column of liquid all more or less at the same
temperature — no kinks or flat spots in the tubing, and no
air bubbles. Below are some common problems you may
Uneven expansion. Both water and alcohol-based
antifreeze expand dramatically when they warm up, so leaving half
of your tubing in the shade and the other half baking in the direct
summer sun can throw things off as much as 3/8 inch between
readings. The smaller the diameter of tubing you're using, the
worse the effect. If that happens, your best bet is to refill the
level from the gallon jug to even out the temperature of the
Kinks. The liquid needs to be able to flow freely
in the tubing while in use. Kinks (or greenhorns stepping or
kneeling on the tubing) will completely throw off your results. A
little education here goes a long way.
Air bubbles. If all you're doing is shooting rough
grade, a couple of small bubbles won't make a huge difference
(Figure 5). However, if you're leveling piers or trying to lay out
stairs, you need accuracy, and every air bubble in your level is a
variable that will throw off your results. No matter how careful I
am, bumping around in my truck always seems to introduce air
bubbles to the level. For that reason, I refill my water level
every time I use it. Siphoning in new liquid gets rid of the air
Figure 5. Bubbles in the fluid ruin a level's
accuracy. To get rid of them, simply refill the tube. Kinks are
bad, too, so don't step on the hose. Finally, a temperature
differential can affect accuracy, so avoid using a water level half
in the sun and half in the shade.
Once you've gotten used to the simplicity and economy of a water
level, you'll wonder why anyone would spend more on tools that
aren't any easier to use and are a heck of a lot more delicate in
the field. And think — if somebody breaks into your truck,
that $400 laser level is a prime target. Why, a thief would step
right over a coil of vinyl tubing to grab it.
Joe Stoddard is a technology and process
improvement consultant to the building industry. Find him online
moderating the Journal of Light Construction's Computer Solutions
expert forum at www.jlconline.com.