Sandpoint Well Project

Start Date: June 2001

Duration: couple of days

In our area, water is pretty expensive, and there is a 150% sewer charge on top as well.  Also, the ground is pretty much sand except for about 6 inches of top soil that the developer puts down for the grass.  The sand seems to leech the water out of the topsoil so the grass dies very quickly when it gets hot and dry in the summer.  You need to water your lawn if you want it to survive - but it gets expensive quickly. 

I did some quick calcs and figured that if I could get water from a well, paying just for the electricity to pump it, I could pay for a pump, and plumbing parts to put together a well in about 2 summers.

This concept is not new around here.  Driven point wells are common in the area because of the sandy ground and a high water table.  When I researched exactly how to put it all together, there didn't seem to be a lot in the way of resources online so here is a personal account of my well project.

The sketch above gives you a rough idea of what you need to attempt this.  Unfortunately, I didn't think to take a picture of the Sandpoint before I drove it into the ground.  It is about 3' long over all.  It has a steel point on the bottom, and a mesh section about 3', then an 1-1/4" female pipe thread.  I bought it at Home Depot.  Home Hardware and TSC carry them as well.  They cost around $75.

I decided to put this in through my basement floor.  I helped my neighbor get one installed before I did mine, so I had a pretty good idea of what I needed to do ahead of time.  The reasons for putting in the basement are: first the basement is closer to the water so you need to dig/drive less, and second once it's in you don't need to worry about freezing in the winter.  I actually put it in before the basement was finished.  The pictures are just from a few days ago when I was making some adjustments.

So I bored a 6" diameter hole through the concrete floor.  Then I used a 2-1/2" thin wall steel tube which I attached to a big shop vac to 'vacuum' a hole down into the dirt.  After a few inches of gravel, the ground was coarse sand which vacuumed up quite well.  There were a few cuts made in the end of the steel tube which I hammered out to act like 'teeth' (imagine a carbide tipped core drill) to help break up the sand.  Between using this tube, then the tube and shop vac extension, I was able to vacuum a hole 7' deep.  This definitely won't work in all ground conditions, but in sand it's worth a try - just make sure you get the biggest shop vac you can find - it makes a big difference.

Next I took the Sandpoint, and threaded onto a section of schedule 40 1-1/2" galvanized pipe.  Use teflon tape or good pipe dope to seal all joints.  You definitely don't want to have an air leak or else you'll be pulling it out later to fix it.  On the end of the pipe, you put a coupler and a nipple.  This prevents the pipe from getting damaged while you hammer it into the ground.

As your pipe is getting driven down, you should observe water sitting in the pipe.  Water should seep in through the sandpoint mesh once you get to the water table.  In my case, I drove the tip of the point down 17' and I had about 6' depth of water sitting in the pipe.  I ran the pump like this for about 5 years without any problems.  I was using a 1/2 horsepower pump.  After about 5 years, I noticed my water pressure was a bit lower, so I started messing around with things.  I backwashed the point, and made a gain of about 2-4 psi while running.  I was hoping for more so when I saw a 1 hp shallow well pump for a great deal, I bought it and hooked it up and sold my other pump.  Unfortunately, things got worse!  The 1 hp pump would produce a lot more water at higher pressure but only for about 30 minutes, then flow and pressure dropped way off.  I could see air bubbles in the pump discharge.  Remember I said I had about 6' of water depth?  I'm quite sure what was happening was the bigger pump was pulling more water out of the sand, so after running for about 30 minutes, the sand at the top of the point was dry and allowing a bit of air to get sucked in.  Once air gets sucked in, the pump loses all its power, if it continues to pump at all.  These are pictures of me adding a 3' section of pipe and driving the point down further.  Now I am 20' to the point, and have about 9' of water sitting in the pipe.  The problem has gone away and I'm getting more water at higher pressure than I had with the 1/2 hp pump.  I've read that 5' is the minimum amount of water that you want sitting in your pipe above the top of your sandpoint (see diagram above).

Once you've driven your point and pipe into the ground, you need to put a check valve at the top to prevent the water from going back down the well when your pump is not running.  If this happens, your pump will cycle on and off all the time.

When I was finishing the basement, I ran copper 3/4" pipe through the walls/ceiling to both the front of the house and the rear of the house.  This is how I get the water out to where I want to use it.  Something to note, the water is so cold coming out of the ground that I used to get lots of condensation on the copper pipe.  To prevent drips all over the place, I insulated the pipe which corrected that problem.  Since the water is not intended for drinking, you could probably use a less expensive pipe like poly pipe if you wanted to save some material cost.  I've assisted 5 or 6 other people with installing these and we used poly pipe instead which is faster and cheaper.

The surge tank you see in the picture is a 5 gal tank with a rubber bladder inside (very common at your hardware store).  The purpose of the tank is to provide a small 'buffer' to prevent the pump from cycling on and off constantly while you're using the water.  These pumps have a pressure switch that turns the pump on when it gets below a certain pressure (eg 30 psi) and off when it gets to a certain pressure (eg 50 psi).  When I run a single hose full open, my pump kicks on and runs constantly at about 35 psi.  When I turn the hose off, it runs for about another 30 seconds until the pressure has built up to about 50 psi.  The key thing is you want your pump to run continuously while you are doing whatever it is that you do most (eg watering the lawn).  If your pump is cycling on and off, it will shorten the life of your motor considerably.  You can prevent cycling by either adding more sprinklers, or adjusting the pressure switch up so that it shuts off at a higher pressure.  Back to the surge tank... If you don't have a surge tank, then there is nothing 'compressible' in the system and your pump will likely go on and off due to the pressure going up and down from 50 to 30 psi almost instantaneously.

Priming the pump takes a bit of getting used to.  Read the instructions with your pump about priming.  If you have a set-up like mine where the section of pipe between the pump inlet and the check valve is very short (only a few feet), then it will take multiple prime attempts.  If your pump instructions say 'pour water in the top of the pump', replace plug, turn on pump, may need to be repeated 2 or 3 times... in my case with my first pump, I'd have to repeat about 10-12 times before I'd get it primed.  The pump shown has a much larger pump casing, and it seems to prime in 2 or 3 attempts.  The key to remember is that every time you prime and start the pump, you are pulling water up your well pipe until the pump gets air.  In my case I needed to pull water up the pipe about 10' and each time I'd prime the pump would only take about 1/2 litre of water.  That's a lot of little 'sucks', if that makes any sense.

hmm... what else can I share about these things... About 100 meters behind my house is a swampy area in a forest.  There is a pond there.  I can get a good sense of where the ground water table is by the water level in the pond.  In spring it is high, and in the dry part of summer, it drops about 3-4 ft.  Since we have water nearby and the ground is primarily sand, my pump/well has been extremely reliable.  For 5-6 years now, I've run it during summer to feed an in-ground sprinkler system that runs for about 2-3 hours to cycle through all the zones.  Normally I will run it every other day.