What is Acceptable Flow Rate?

[NSBound]

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]

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_]

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]

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]

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]

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_]

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

 

[NSBound]

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]

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_]

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.

 

[ByronBob]

When my well was drilled my guy mentioned if it was 3gpm or less that I'd need to have a holding tank as they have under the deck. He said you can live this way but you couldn't water the lawn, take a shower and run the wash all at the same time. So common sense prevails I suppose.

Now when buying my first house, the inspector turned on the tub and proceeded to run it for over 30 minutes. When we were all done I asked him what he was doing and he told me checking water volume. He said if the system didn't dry up after running water for that long that my water volume wasn't going to be a problem.

Still the very concerns you have are going to be had by the next people to buy the house. Make sure you think this through.

 

[NSBound]

[Thanks all for your thoughts, comments and calculations. You are likely right about the size of the tank under the deck. For watering the lawn and washing the car, I guess, the current owner has also installed 2 more tanks (painted green) for collecting water - see next attached photo here.

I will definitely have another look before I leap, and I may pass - am thinking hard because it's otherwise a very nice house with a garage/shop I'd love to have.

 

[Junkman]

Have you asked the present owner of the house why he has all those tanks? Seems strange that they would be outside when it gets cold in Canada, and freezing is a possibility. I don't remember the rate for my well, but I do remember that it was quite low. I have never been able to pull it down dry and I water the lawn and use lots of water. I wouldn't be afraid of the water situation unless I learned from a reliable source, such as a well digger, that the well was deficient. It might even be possible to find out from the company that drilled the well, what the true situation is. If they are still around, they should have the drilling records.

 

[_RaT_]

The two tanks that catch water run off from the roof look like just a dabble in water conservation. I would think at most you could do a little drip system with them, but irrigate much more then a small drip system and those tanks would empty pretty fast. On the otherhand, do you need to irrigate much? If not, the 1000 gallon tank would certainly make the domestic supply very useable.

 

[ByronBob]

Ask yourself if you own this house would you be scared about the water situation to throw a huge chunk of money onto it only to run out at some point during the year? Sure you can buy water if you need to but that defeats the purpose.

Could you drill deeper? Do the neighbors have this problem? How deep is the well? How deep are the neighbors? I asked every neighbor around me when I built how deep their wells were so I knew where I'd end up at.

 

[_RaT_]

Good points, well worth looking into.

 

[Junkman]

I asked the neighbors and all of theres were at 100-130 feet... mine came in at well over 400 feet.... just don't remember how much, because I still haven't gotten over the cost yet and that was over 20 years ago. The last time I pulled the well pump, a friend helped. He asked if I had portable radio's so he would know when the pump was out of the well, because he was out of shouting range... /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

 

[hitekcountry]

In the County where I live the min is 3gpm req to obtain a permit to build a house.

Everyone in this ares has holding tanks to store water. the reason is that wells (in our area) produce less in the summer and it’s not uncommon to hear that a neighbors well is producing less than is being used. And it’s not uncommon in the summer to see the water truck delivering a load of water to someone.

So as an example lets say it’s summer and your well is producing 200g/day less than what you’re using. And lets say you have a 12,000g storage tank. what that means then is that you can go 60days before you run out and need to order a truck load of water. Now lets say that this short fall condition only occurs 30 days at the end of every summer. You don’t have a problem.

I have 7,000g of storage and never run out of water. One of my neighbors has 20,000g of storage and still has 4,000g water delivered 3 times a week in the summer time. It’s a long story.

Fred

 

[_RaT_]

I have a relative in Livermore who has 2 10,000 gallon storage tanks. His well is fine but inorder to start construction on a remodel, he needed fire suppresion water available. Found two used plastic 10,000 gallon tanks that a fire truck can suck out of. Myself, we have high yield wells, as well as ditch water irrigation. With that I have about 120 GPM at 120 PSI.

 

[hitekcountry]

Rat

Around here 15gpm would be someting to brag about...... <font color="red">120GPM!! </font> you sure know how to hurt a guy! /forums/images/graemlins/mad.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif