What is a good flow rate from a well?

Which gives us:

Potential flow rate: How much water comes into the well if you remove it all. This is the good number to know, but typically was measured when the well was dug, and typically pumps & pipes are sized to deliver less than this number so one can't tell without an expensive test.

Actual flow rate: What your pump & pipe supply at maximum flow. Should be less than potential, or you will be starving your pump, adding air, & causing problems. This is the number you will likely get. To find it, need to pump water out for 1/2 hour or so steady, & then measure the flow rate - if you don't let the pump run full for a while, you may only be mesasuring the drawdown, not the actual steady flow.

Drawdown supply: How much water is sitting in the well casing pipe, which can be drawn out very quickly. But once empty, then the pump will draw air if the well itself can't resupply water that fast. This is important in slow-supplying wells (or shallow wells 3' across too), as mentioned by others.

--->Paul

When I had mine drilled eight years ago, they went 175 feet and got 67 gpm.... Said I had enough to water the community.... PTL!

Out in the west with less than 7 inches of moisture per year (in the winter) you need 10 gallons per minute for every acre you want to farm or garden.

I stand corrected. I don't have any idea what the flow rate for my water well is.

I do know that after six hours of steadily pumping irrigation water my submersible pump will still put out 35 gallons per minute, measured by doing a timed test by redirecting water flow from my 2" line into three 5 gallon buckets.

The well does not "draw down" meaning it inflows as fast as my pump can remove 35 gpm. It has 85 feet of water in the casing before testing and during testing. The well has 5" casing if you are interested. I wish now that I had gone with 6".

I am impressed they got a 2" pipe & a pump to handle that flow in a 5" casing.

Was common to put in 4" casing around here in years past, pumps were so tight fitting that often they stick in & the well is shot then. Dad for one of the few times spent extra & went for the 5 inch casing back then.

--->Paul

In some areas the time of year the pump test is done will influence output. One of the wells on our poperty was rated at 25 gallons per minute....based on the well log when it was drilled in Feb. That same well, driven 110 feet until it hit granite, in August will put out one quart per minute.....you need to be creative to get the most out of a well like that. This water was mostly 'groundwater' sitting on top of a big granite outcrop and it has lots of iron in it which is another pain to deal with. We later drilled a well 280 feet deep into the granite and hit some water, not much mind you, and this well produces 1/2-3/4 gpm no matter what the time of year it is....and it is nice clean iron free water! With proper storage, liquid level and pump controls we have no problem raising all the critters we want and as large a garden as we can handle for the two of us....unless you leave a faucet open then you start over!

I think that the line in the well holding the pump is 1 1/2" black polyethylene. It connects to a pitless adapter below the frost line. At the adapter on the outside of the well I connected to it with a 1 1/2" X 2" fitting. By using 2" line there is less friction loss in the piping which allows the pump easier pumping.

The pump is a Grundfos 1 horsepower unit with enough capacity to irrigate 50 rows of market garden crops at once with T-Tape drip irrigation.

It has been awhile since I've actually market gardened. When I still planted I planted with rows 200' in length fed off of 2" pipe. T-Tape purchases were in 6,000' rolls yielding a cost of about 3 cents per foot plus fittings.

I hope this information isn't considered as hi-jacking the thread.

Chris -- in Ontario, this is one of the questions that buyers will ask. They may also ask you to get the water tested (shades of Walkerton, I guess). Don't let it put you off .... if they like the house a rate of 3 gallons won't put them off. Get it rated and assure them that it has been sufficient for your family's needs (assuming that it has). Don't lie ... if it's been aproblem, be upfront because they can come back at you for a number ofyears if it turns out that you deliberately misled the buyer.

My rate is 5 gal. a minute in a 126' drilled well.