What is Acceptable Flow Rate?

NSBound · Mar 25, 2005

I'm looki ng at buying a house that will likely be on well & Septic, and have been advised to make the offer to purchase conditional on a "well flow test". I did so, and guess I'm glad I did as the first vendors refused to permit the test to be done! But now, they are having their own test done and say they will share the results with me. This apparently is in a subdivision where there are known areas of good water volume and other pockets where water supply is a known problem.

My question I guess is, if they do have a flow test result to share, what is an "acceptable" flow rate? I am just one person but when I sell the house in 2-4 years' time, I don't want water availability to be a problem for the purchaser(s), especially if it's to a family of say 3 or 4 or 5 people.

Any thoughts???

mathey · Mar 25, 2005

Not sure how it is where you are, but here there are requirements on minimum flow...generally 1 gpm in order for the property to be legally sold. Your realtor or local permits office/health department should be able to advise you on specifics.

A guy I work with just went through this...his existing well was behind his house where he'd like to do an addition, so he decided to redrill in the front. First hole was 300ft, and less than the 1gpm. Second hole 600+ feet, still less than 1 gpm. Ended up fracturing six times at various levels in order to get above the 1 gpm requirement. And although his reserve was suffucient at less than the 1 gpm, he could never have sold the property. Summary? an extra $10K tacked onto the original addition cost.

_RaT_ · Mar 25, 2005

Out here I believe we need to have a 2 gpm flow rate minimum. With that low of a flow rate, folks would typically put in a submerged tank that can fill day or night from the submersible well pump and hold 1500 to 3000 gallons with a second pump in the tank to then supply and charge the domestic water. That pump does not have to be substantial because it only needs to charge the system to 60 PSI plus any rise to the house. The big benefit is with several thousand gallons, you have plenty of reserve for almost any situation. The well pump only needs to have enough pressure to lift water into the tank and not to the house with the additional charge pressure.

Egon · Mar 25, 2005

Don't know what legal and bank flow rates are required.

2 gpm will do nicely for a small household.

Depth and source and quality of water may also be facts to consider.

Depending on the type of well the water supply and quality may vary greatly throughout the season.

Egon /forums/images/graemlins/grin.gif

engineer · Mar 25, 2005

When getting a subdivision permitted here in New York the NYS Health Dept. typically requires a minimum of 5 gpm yield from wells to serve a single family home. Sometimes for wells with yield between 2 and 3 gpm you can over size the hydropneumatic tank to help maintain pressure and flow through out the residence. personally I would find a well with less than 5 gpm highly undesirable.

engineer

MadReferee · Mar 25, 2005

My well is down 360' and the recovery rate is just over 1 gpm. With the static level coming up to almost the top of the well and the majority of the well hole being 6" diameter, there is over 500 gallons of water in the well. It has served our family of 5 very well for the last 27 years. We have never had water shortages.

_RaT_ · Mar 25, 2005

That is a nice way to have a well if the recovery rate is low.

NSBound · Mar 26, 2005

Thanks so far for all the comments! Sounds lioke 2-5 gpm would suffice. I neglected to mention that there is an 11,000 gallon cistern located under the rear deck of the house. (see attachment). That alone should have told me there is a water supply issue! I will advise further as I find out more.

Junkman · Mar 27, 2005

I believe that might be a 1000 gallon tank.. A 11,000 gallon tank would be much larger....... extremely much larger... and bigger than that...... /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

Gallons : 10500
Diameter x Height : 142" x 168"
Weight : 2500 lbs
web page

While poking around the site of the tank company, I came across this web page that might just be what you are looking for. After reading about the product, it seems that it will take care of the low producing well, but I don't know at what the $$$$$$ cost will be.. Junk...

_RaT_ · Mar 27, 2005

In fact, just to give you an idea, a double tanker gas truck carries about 4000 gallons in each tank for a total of 8000 gallons. 1000 gallons for that size would seem about right.