Water Pump

[Adam Roby]

Hi All,

A buddy of mine just bought a cabin up north at a steal,  but it has a lot of problems.  It was a repossession from the bank, so the PO let the place run down quite a bit. 

He has a question about the existing water pump, but doesn't know any details about the well, where it is, how deep or anything like that.
The pump I assume wasn't working so he is repairing it.

Just picked up the replacement parts for the water pump.. the pump was
filled with very fine dirt/sand that turned into stone after sitting
for a year.. so... I know the water needs filtering.. and it needs it
before the pump.. but there's like almost 0 info on what you actually
need..

I know that I need to filter in steps like using 3 filters in series
like 30or50um then 20or10um then 1um.. part I don't get..

Problem 1: Flow... with these filters in front of the pump.. it must
restrict the flow quite a bit .. would that harm the pump etc.. etc..
or do I need to put the fine filter (1um etc..) after the pump/tank or
not need it at all (aka it's not needed to get dirt/silt out?)? What
would I need as a minimum flow rate when the pump draws?

Problem 2: which filters.. it seems like the "housings" come in
standard sizes 10" x 2.5" being the most common/$$$ effective.. I see
larger one.. but the price skyrockets.. is this right that the
housing/filters are standard?
Is that the size I should be looking at using?

Sorry if all the info isn't there.  I will forward any questions you have to him if you need more details.

[JRR]

Is there a well?  What is it's depth?  What style pump is used...submerged ... jet ..etc??

[Adam Roby]

"drawn from a lake..

end of the pipe is "supposed" to have a "lake screen" but I don't know
what's holding it down.. I assume it either buried gravel or anchored
to something and a bit above the bottom..

Depth based on where I think it is.. about 4-5' deep
3/4 HP shallow well jet pump, 16 gallon pressure tank (all in the house)"

[JRR]

The pump's performance will be determined by the vertical distance from the pump to the level of the lake, not the depth of the jet ... so I would consider raising the jet off the bottom far enough to prevent induction of particulates.  Of course the jet alos has to be deep enough to avoid air induction.  Should be an easy solution.  (At least for someone who doesn't have to do it ..!)

[Adam Roby]

What about the filtering question, is it something that needs to be done before the intake to the pump?
Sizes, number of filters.. etc.  Is it just normal to have those particles go through the pump?
He wants to avoid causing more damage to the pump if it can be avoided.

[JRR]

Well, you always need a screen ... but if the pick-up is located, off the bottom, in somewhat clear water: I would think particulates drafted into the pump would be almost a non-issue.  Of course, if the pond is muddy by nature ... there is no "clear" water.  Depends.

[pmichelsen]

This setup sounds a lot like my setup. We gravity feed our 5000 gallon tank from a stream that flanks the property and then pump it from there to the cabin....

On the stream side we have a filter box made out of an old christy's box, in the side of the box we drilled a hole for our pipe, the pipe is capped and we drilled a bunch of holes in the length that is inside the box, we then covered the pipe with some fine mesh, and finally filled the box with gravel. This filters out most of the big stuff.

We then have two filters after the pump as seen in the photo below. We use Pentek housings (1 1/2" inlet/outlet), they allow for different sized filters based on your filtration needs.

[waggin]

We had a similar setup at a place in New Hampshire and never filtered at all.  We used the water for everything except drinking.  Granted, it was a very clean lake!  If the lake water at your buddy's place isn't REALLY silty, then I'm guessing the inlet fell on/into the silt on the bottom.  Ours was in about 3' of water with only a lake screen at the pickup end, and it was run through a cinderblock standing on end, braced with some rocks around it.  Very low-tech, but it worked great for decades.  If I was doing it again, I'd add some filters like pmichelsen did.  Assuming the water is clear or even semi-clear, it sounds like the pickup simply fell onto the bottom and sucked the silt/sediment into the pump. 

The existing system sounds a lot like the one we had.  Working with systems like this have advantages like cheap parts and easy access!

[pmichelsen]

Another option for keeping his inlet out of the mud is to tie it to a buoy, or for something with more character he could use a goose decoy.