Well Drilled - Results

   / Well Drilled - Results #1  
Pettrix

Pettrix

Platinum Member
Joined
Jan 17, 2012
Messages
595
Location
High Desert Southwest
My well was drilled today:

Drilling Type = Air Rotary
Well Depth = 505 feet
Static Water Level - 220 feet
Water GPM = 20
Perforated Pipe = 280 feet - 500 feet (20' pipe sections every 20 feet - 100 feet total of perforated PVC pipe)

The well driller said that the 20GPM is "conservative" since they measure the GPM during drilling by taking a bucket and timing how long it takes to fill. He said the well will produce more GPM since the drilling rig is blowing air into the well and this prevents the well from filling normally. He also said that debris can clog the water vains during drilling and that can reduce GPM.

Is the above true?

The well driller claims the only true test is once the well pump is installed one then can get a proper GPM reading.
 
   / Well Drilled - Results #2  
Once the pump is installed the rate you will get is only what the pump can manage under those conditions.
 
   / Well Drilled - Results #3  
That's a pretty deep well but good flow. Was your well drilled through rock as I have heard that can temporarily clog. What part of the country are you in?
 
   / Well Drilled - Results #4  
A sustained flow of 20gpm is more than adequate for home use. Drilling can plug the aquifer - that's why many times the well is surged. Surging is designed to remove the sediments, open the water bearing strata & increase flow.
 
   / Well Drilled - Results
  • Thread Starter
#5  
sixdogs said:
That's a pretty deep well but good flow. Was your well drilled through rock as I have heard that can temporarily clog. What part of the country are you in?
Click to expand...

I am in Northern Arizona (5,000 feet elevation)
 
   / Well Drilled - Results #6  
That's one deep hole! Out here they pump the well completely as they can and then measure the recovery.

How did they locate the water, did they witch for it?
 
   / Well Drilled - Results
  • Thread Starter
#7  
Trials said:
That's one deep hole! Out here they pump the well completely as they can and then measure the recovery.

How did they locate the water, did they witch for it?
Click to expand...

They didn't do that. While drilling with the air rotary they constantly have air pressure blowing into the hole and then a pipe which is dumping the air, water, rock and debris out of the hole.

So at this pipe end they take a bucket and time it on how long it take to fill the bucket. That is the ballpark conservative GPM.

It's not 100% accurate but conservative because the air blasting into the hole is preventing the well area from filling it with water. Think of it as a straw but you are blowing air instead of sucking the water up.

Ideally, like you mentioned, having the well fill up without any back pressure like air blasting into it and then pumping and measuring the refill rate is the best way to measure it.
 
   / Well Drilled - Results #8  
Is this a 4 inch well, or a 6 inch well???
 
   / Well Drilled - Results #9  
Blowing will give you an estimate. But you really can't tell how much a well will make until you test pump it.
 
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