This simple tool has been in use for thousands of years ... literally. The earliest credit for invention that I could find was to Theodorus of Samos (Greece) in the 6th century BC. So assuming he was the first to make a water level, it has been in existence and use for over 2500 years.
The concept is simple. Water will always try to find it's own level. What that means is that water will fill whatever container it is in and the top of one side will be the same height as the top of the other.
The water Level is a simple low tech solution to finding levels regardless of distances (as long as you have enough tubing) or other conditions.
There are two basic ways I know how to use the level.
1) Set the reservoir at the height you want and then move your measuring end around to find the same level at a distance. Great for laying out the framework for a deck extension. (stay tuned I show you this method in a later step)
2) Set up the level and zero the measurement for point A. You can now determine the variance in height from point A for points B through Z. Great for finding out the rise/fall over a distance. As you can see from looking at the first two pictures in this step I set up my level as far from the porch as it would reach (about 15 feet) then I zeroed the measure. Moving up to the base of the step I was able to determine that the ground there (point B)was 9 inches higher than point A.
Step 1: Materials
Clear Tubing - The clear tubing makes it easier to verify that you don't have any air bubbles in the line. Bubbles in the line will cause the level to read inaccurately.( just over $5)
Reservoir Container - I got a lidded quart container from the paint section in the big box store for less than $2. The lid is great for keeping debris out of the reservoir and preventing accidental spills if the reservoir gets bumped. Just remember to drill a small hole in the lid to vent air or the level accuracy will be affected. (less than $2)
Drill and bits - I used a 3/8" bit for the hole for the tubing in the reservoir and 1/8" bit for the vent hole in the lid.
Adhesive - for fixing the tubing into the reservoir and preventing leaking. I used E6000 because it is waterproof and stays flexible.
Yard Stick - For measuring variance of height. (under $1)
Coping Saw, Clamps, and Wood Glue - For modifying the yard stick.
Clear Tape - Used to attach the working end of the tubing to the modified yardstick.
Velcro Straps - Holds the modified yardstick and tubing onto the push broom handle.
Push Broom Handle - Used to hold the working end of the level. You can use any sort of stick you prefer, the push broom handle was what I had handy.
Step 2: Prepping the Reservoir
Drill a hole in the side of your container (near the bottom) the same diameter as the outer diameter of your tubing.
Drill a small vent hole in the lid of the container.
Realize that in any water level the reference level changes level as you move the working end up or down.
In a pinch you can make a level out of just a length of tubing and some water.
There's more than one problem with this technique:
1) You either need two people or some impressive taping skills to secure one end while you measure with the other.
2) Using just tubing the movement of the water is a 1:1 ratio, so if you are off by a 1/2 inch on the reference end you will be off by a 1/2 inch on the measuring end as well.
If you instead use a reservoir, you have two major advantages over just tubing:
1) You can use this by yourself, all you need is a solid location to place your reservoir so it doesn't tip over and spill.
2) The amount of height change is determined by the ratio of surface area of the reference end to the surface area of the working end. To put that in perspective, The reservoir has a 5" diameter, and the tubing has an inner diameter of 1/4" . that is a 400 to 1 surface area ratio. The working end would have to move up or down 25" to change the level in the reservoir 1/16th of an inch.
Step 3: Affixing the Tubing
Once you have the hole drilled you simply need to push the tubing through the hole in the reservoir.
Pull the tubing through so you can apply an even amount of glue near the end of the tubing.
Pull the tubing back through the hole until the glue seals against the container (be careful not to get glue over the opening of the tube)
Run a bead of glue around the tubing on the outside of the container as well.
Wait for the glue to cure.
Step 4: Making Your Measuring Meter
You can get a yardstick from the paint department of your local big box store for under a dollar.
Using the coping saw, cut the yard stick in half.
Line up the ends of the yard stick so that the numbers are counting up going away from the center.
Apply a layer of wood glue to the ends and clamp them together while they dry.
I made the mistake of clamping the yardstick on a scrap of 2x4 without anything underneath. When I went to remove the yardstick I had to pry it off the 2x4 because of a bit of glue that squeezed out during the drying process. If I need to make another one of these I will remember to put a spacer (2 quarters would do the trick)under the yardstick in case of drips.
Step 5: Final Assembly
Using the clear packing tape, secure the working end of the tubing to the modified yardstick.
Drill a small hole in the end of the yardstick where the end of the tubing is.
Tie a string through the hole you drilled. You will use this to adjust the height of the yardstick on the push broom handle.
Use the Velcro straps to secure the yard stick to the push broom handle.
I was originally going to use a binder clip to secure the string, but the string was not held securely enough. I found it was easier to just tie a clove hitch knot to secure the string in place on the handle.
Step 6: Setting Up the Level
To make the water easier to see in the reservoir and the tubing I added a few drops of food coloring to the water.
Make sure there are no air bubbles in your tubing. Air bubbles will drastically affect the accuracy of the level.
As you move the working end of the level around you will notice the water bobbing up and down. That is normal, it settles down very quickly once you stop moving the level.
Remember that if any water spills out of the level during use, either from the tubing or the reservoir, you will need to recalibrate your level.
Step 7: Testing the Level
Here is the explanation for one way to use the level I told you about in the intro.
Set up the level reservoir in line with the edge of the deck.
Bring the working end of the level out to the point you want to extend the deck (I used the pole that the clothes line used to be attached to).
Mark your level line (camo duct tape to the rescue)
String a line tightly from the deck to the point you marked (This is where a junior helper comes in really handy).
Set up the spirit level on the string and verify that everything is level.
Step 8: You Can't Do That (With Other Levels)
A distinct advantage that water levels have over other types of levels like string or laser levels, is that a water level can go around corners and out of line of sight from the point of reference and still indicate where the line of level is.