Water pressure issue with irrigation and home

[magic1141]

Hello,
I was hoping someone could help with an issue I am having with well water pressure. Well is 90 ft deep with 6 inch casing, hit water at 20'. Drilled down to 90'. Set 1/2 hp sub pump at 80'. Have 35 gallon pressure tank installed also. All done by well installer. Was told well was giving out 13gpm. I was told this would be enough cover a 12 zone rainbird irrigation system and a 3 bed 2 bath home. It is only the wife and I though. Most wells drilled around here are 160' ft deep with 1 hp sub pump on them. Of course, irrigation put in and by the time it gets to middle zones it is decreasing in pressure and pulsating. When outside faucet is turned on, there is no pressure for the sprinkler heads. Do not have home finished enough to see inside pressure while sprinklers are going but I know this is not good. Well installer said to just water at night and there MIGHT be enough pressure for a shower. The well installer said that going deeper and putting a bigger horsepower sub pump would not make a difference, I am asking someone to explain to me how this would not help the matter. Also, if someone has other solutions they would be greatly appreciated. I am sure I am leaving some much needed info out and will be glad to provide, ( I am a newbie to all this). Thank you very much for any response.

 

[MI Well Drilling]

When you say pulsating do you mean air? When you notice this happening go out to the well head and listen for a slurping sound. If you do than the well man that installed it only drilled a good enough well for a 1/2 pump and no way would a 1 horse be better because it would pull the water out of the well faster than the little 1/2 hp is. The term is called drawing down. It means the pump is asking for more water than the well itself will give. If the neighbor is not having problems contact their guy.

 

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[ThirdGenPump]

On your irrigation you need to know how many heads per zone and how many gpm each head draws.

It sounds like you are out pumping the well. As MI said a larger pump won't help if you don't have enough water.

Try putting breaks in your irrigation schedule. Water zone 1 30 minutes. Rest 30 minutes. Water zone 2 30 minutes. Etc. That will give the well a chance to recover between each zone so the pump can pump at peak capacity.

 

[MI Well Drilling]

Although playing the zone game sounds fun. The home isn't even finished and he's having trouble. Imagine 10 years from now when the well screen is half plugged and the house is full of relatives using the toilets and the wife is doing loads of laundry and pulsating starts. If the well is showing trouble with drawing down now than personally i would investigate why the neighborhood wells are 160' and are capable of irrigation with a 1 horse.

 

[Reach4]

Set 1/2 hp sub pump at 80'. Have 35 gallon pressure tank installed also.

A 1/2 HP pump with the water level at 50 or 60 ft could give 10 gallons per minute. How long does your pump run at minimum?

 

[ThirdGenPump]

Miss-read the first post. He said 'going deeper would not make a difference?' Not sure why he would think that. Even if they made no gains it would give more reserve to work with.

 

[magic1141]

Miss-read the first post. He said 'going deeper would not make a difference?' Not sure why he would think that. Even if they made no gains it would give more reserve to work with.

Thank you all for all the quick responses, that is my main question,"Why will going deeper and a bigger pump not make a difference?" I was hoping that someone could explain why this wouldn't make a difference, or if I am just being led astray because they didn't drill deep enough in the first place and they do not want to mess with redrilling it.
Also, Reach4, the pump is on a 40/60 pressure switch and will pump for approx 1min 45 secs to build up and then it takes 1min 30secs to drop to 42psi.

 

[Valveman]

OK you have a 10 GPM pump and a tank that holds 8 gallons of water. If it is running 1:45 on and 1:30 off, then you are using about 5 GPM. Using less than 10 GPM is causing your pump to cycle on and off, which is what I think you are calling "pulsating". If the pump is still cycling on and off between 40 and 60 while the sprinklers are running, you are not running out of water and the pump is plenty large enough. If the pressure just goes low and stays there, then either the well is not producing as much as you are using, or the pump is not producing as much as you are using.

If the pump cycling on and off is causing the problem, a Cycle Stop Valve will solve that problem.

If the pressure just stay low, you need to figure out if the pump is putting out the 10+ GPM it should, or if the well is making less than 10 GPM.

 

[MI Well Drilling]

In the original post your saying that when the outside faucet is on at the same time as the irrigation the pressure is very low and pulsating. If the pump were cycling on and off during that time the pressure at the outside faucet would remain decent. Don't bother with the cycle stop. What you should do is listen at the well when the pulsating starts if you hear a slurping sound that would help the rest of us understand the situation. If you don't hear a slurping sound than that would be great news. What I'm getting at by saying go deeper is that down deeper may be a more productive water vein that will support a larger pump plus you gain more static in the well therfore more draw down capability.

 

[Valveman]

Also, Reach4, the pump is on a 40/60 pressure switch and will pump for approx 1min 45 secs to build up and then it takes 1min 30secs to drop to 42psi.

If the pump is cycling like this while the sprinklers are running, you are not pumping the well dry and you will not hear any "slurping". But if the pressure is low and stays low, like 20 PSI, you maybe pumping the well dry and could hear "slurping".

If you are pumping the well dry you need a Cycle Sensor dry well protection relay to save the pump. If the pressure is just low because the pump is continually cycling on and off, then a Cycle Stop Valve will solve that problem.

Opening the outside faucet, especially if it is a frost free type hydrant, is probably just using all the water the pump can produce, so there is no water left for the sprinklers.

 

[MI Well Drilling]

Not to argue but if the pump was making enough water for the system to pump up to full pressure and shut off then drain down and kick back on don't you think that would mean the pressure should stay good everywhere. Low pressure in this situation is one of two things. The pump is too small or the well is drawing down. I've drilled andiinstalled thousands of wells and pumps so I'm kinda familiar with it. I feel that a cycle stop is a waste of time and money. I have three in my trash can now. Listen out at the well and let me know.

 

[Valveman]

Not to argue with you, but if you put Cycle Stop Valves in the trash and think they are a waste of money, then you have no idea how they work. You should look at the references and reviews to see what customers think about Cycle Stop Valves. The three you have in the trash can are still under warranty if they failed to work. But usually it is the installer who fails to know how they work, and there is nothing wrong with the CSV.

I agree that low pressure is either too small of a pump or the well is pulling down, but it can't be low pressure AND cycling every 1 minute and 45 seconds. So the question is, does the pump cycle on/off all the time water is being used, or is it running constant and just not producing pressure?

 

[MI Well Drilling]

And pulsating! Cycle stop valves are a great thing when installed under a trailer house. I personally remove them after they plug with rust then simply size the pump and tank to operate demand. My apologies to the owner of this post for this turning into a cycle stop discussion. The original post says "not enough pressure, only water at night and you'll have enough for a shower". I've been drilling wells for 22 years, I've heard this before. The well is not giving enough water or the pump is too small. Yes it has a run time of a minute or so but that's just using the outside tap. I'm sure when the irrigation is on it's not shutting off at all. Good luck guys

 

[Valveman]

Sometimes people call it "pulsating" when it is really just cycling. I have been in this business close to 50 years, and have learned to keep asking questions until I get to the real problem.

I think the pump is cycling on and off when the irrigation system is running, and when the hydrant is also opened, there is not enough flow for both and the pressure goes low. But we won't know unless the OP comes back and tells us if the pump is turning on and off while the sprinklers are running.

CSV's do not rust. And they don't get plugged up with rust from the well anymore than a pressure switch, pressure tank, or any other part of the system.

 

[Reach4]

Do not have home finished enough to see inside pressure while sprinklers are going but I know this is not good.

I think you are saying you cannot read the pressure gauge while the sprinklers are going. That is pretty odd. You could put a pressure gauge on an outside hose spigot.

 

[MI Well Drilling]

Solid rust chunks do plug them. A cycle stop isn't going to fix the issue the way your talking he needs a bigger pump. I'm going to leave this one alone and let valve guy figure out the well issue and not the well guy.

 

[Valveman]

Solid rust chunks do plug them. A cycle stop isn't going to fix the issue the way your talking he needs a bigger pump. I'm going to leave this one alone and let valve guy figure out the well issue and not the well guy.

You could be right. But the OP has me confused. Either it is cycling on and off, which means the well is good and the pump is large enough. Or it is not cycling and the well is weak and/or the pump is too small.

I was a well guy for decades before I became a valve guy. But now I am a "trying to figure out what the OP is talking about guy".

 

[MI Well Drilling]

Hopefully he sticks with it. When I first read the post I was dead set on the well drawing down. Sorry about going off course. I assume that the well driller knew irrigation was going to be put in but the well doesn't produce so he dumped a 12 gpm pump in and told him to water at night while you're sleeping so they wouldn't run out of water. If the well gave enough water darn Skippy the driller would have pushed to sell a 1 horse and a bigger tank. Heck the well might have a lemco seal above the pump and it wouldn't suck air it would just pump slow. Lots of if. If the fox didn't stop to sh#t he'd have caught the rabbit.