Wells: Testing water level

GlueGuy · Jul 29, 2001

Since this appears to be "well week" (are you all feeling well?!?), I thought I might pop this one out to see what others have done in this area.

We live on a ridge-top. Since the available aquafer is limited, and we are in a drought, I got to wondering how well our well is doing (sic)... Does anyone have a system for checking the water level in a well, to see what the "draw down" is?

Our well is 450' deep, and the water level was originally around 300' when the well was drilled (5" casing).

The GlueGuy

jinman · Jul 29, 2001

Glueguy, consider this a response from someone who has never done it, but has an idea. In other words, take it with a grain of salt.../w3tcompact/icons/smile.gif I would lift my casing cap and using a piece of monofilament fishing line, tie something on the end that is heavy enough to feel, but will float. Drop it down the well until you get an abrupt change in weight indicating the weight has struck the water. If you aren't almost deaf like me, you could probably hear it (like taking a sounding). Mark the line at the top of the casing, then pull it out and measure it. There are probably better ways, but since you have such a large diameter casing (5") I think that might work. You also have the advantage of knowing approximately where the water should be, so the first 300' or so you can just let it drop. My two cents (or less) worth./w3tcompact/icons/smile.gif

JimI

GlueGuy · Jul 29, 2001

That's one of the considerations, and sounds like a cheap, and relatively accurate way of doing it.

Another suggestion that a neighbor had was to drop a rock into the well, and time how long to the "splash". That didn't sound too accurate to me, as you might be misslead by the rock skipping off the sides or the pipes.

I also heard that some well drillers have a sonar-type device (or is it laser?) that can measure the difference pretty accurately without dropping anything but sound (or light).

Just curious as to what (if anything) others have tried...

The GlueGuy

RPM · Jul 29, 2001

Well, well, (really plumbing the depths here /w3tcompact/icons/crazy.gif)

I had a thought - but haven't tried it yet. I too live on a ridge and my well is 600 feet deep. It's so deep that although the area is known for acid water, mine is actually alkaline - I'm well down into the limestone.

Anyway, I have been thinking about how to check on water level for a while - the best I could come up with (not yet tried) was as follows - first, get hold of a large ball/spool of dark wool and a 300 foot landscape measuring tape. Tape the free ends to the well casing and walk away unravelling them. Tape them together at strategic points. Now attach a weight to the end by the well casing and lower it down. When/if you hear the plop when the weight hits water, pull it back out - the wool/yarn will show you what the water depth was - just read it off the tape. It's basically a glorified dipstick (some would say just like me /w3tcompact/icons/shocked.gif). The dark yarn would be needed as it would be hard to guess the 'wet' mark of a fiberglass / plastic tape. Dark shows the wet better than light etc.

Of course, for a ball-park estimate just use the equation:

depth = 0.5 x g x t x t

Where g is 9.81m/s (about 32.2 feet per second) and 't' is the time in seconds before you hear the 'plop'. Most well casings do a nice job of acoustics so you should hear it alright.

Patrick

looch · Jul 29, 2001

I've never tried this either, but I think this method would work. I would add a fishing bobber (big enough to support the weight) just above the weight. That way you'd know for sure when you hit water. Use a small weight and a 3/4" bobber to avoid hanging it up.

StoneHeartFarm · Jul 30, 2001

Glueguy,

I checked the level in my 2" well using just about the method mentioned. I took some twine (white), tied a small nut to the end and dropped it down the well until it stopped, (there is a bottom). Then I pulled it up quick as I could, found and marked the end of the wet spot, laid it out flat and measured it with a tape. This gives you 2 measurements, depth to water and depth of water. Small wells like the 2" have a foot valve to keep the water from dropping and sucking the pump's prime. Be careful not to get the nut caught in the valve.

SHF

MarkV · Jul 30, 2001

GlueGuy,
The well drillers in this area have a sensor that they lower into the well and it beeps when it reaches water. The problem I would see with the string/yarn method is that collars are attached to the feed pipe to keep it from whipping around when the pump kicks in. I my case, there is one every 30 ft, so I have seventeen of them in the well. It would seem that it would be easy to get a string hung up on one of these collars. If the string were to break you could have real problems if the pump sucked it in.

MarkV

kevincook · Jul 30, 2001

I measure the water levels at several houses in our neighborhood every month. A geologist from the USGS taught me this method several years ago and it works very well.

Using a tape measure (steel preferred) attach a weight to the end of it. I don't like to use lead weights because you will eventually lose the weight in a well. I used a piece of stainless rod. Mark the bottom 5-6 feet with a piece of chalk ( I stole it from the kids). Slowly drop the tape down the well until you hear a splash. Drop the tape down another foot or so and record the measurement on the tape against the top of the well casing. Reel the tape up and record the measurement on the tape where the water has marked the chalk. It will be easy to see the mark on the wet chalk. Subtract the wetted reading from the first reading and you will know the distance from the top of your well casing to the water.

The water level will go up and down throughout the year so a reading taken now will be different than one taken in January, also make sure the pump wasn't run just before the reading. The well will need time to recharge.

Fortunately I don't do it this way anymore. I use an electronic gauge that is faster, but if your just measuring one well it shouldn't make a big difference.

Check out www.solinst.com

GlueGuy · Jul 31, 2001

Kevim,

Thanks! That soinst link was just the thing that I was looking for. There are probably other similar things as well. (very punny)

The GlueGuy