Water storage solutions in a drought

[beowulf]

For 35 years we have lived here on a well with a 1.5 hp pump at 420' and a pressure tank set to 40-60. The last time the yield was tested it was about 21 gpm. We never had any issue with water and we use a good bit with gardening, orchard, landscaping, animals, household, and my wife's countless flower pots and plots. However, this year it is reported to be the third driest year in Cali history and there was an article in the local paper about expectations that many wells may go dry or the yield greatly unreliable. Also many here in the foothills are sharing stories about how wells have gone dry in the past in such circumstances. That got me to thinking that I may want to put in a storage tank just in case.

But because the current plumbing set up is that water comes out of the shaft and into the pressure tank and into the house, I am not certain what my options would be to install a storage tank as a back up. I could put it up the hill side and use it as a valve controlled gravity fed source if needed but the pressure would be quite low. Or, perhaps I could do that but then also add a booster pump between the storage tank and the house but would I then also need another pressure tank or somehow manage the booster pump in some way to turn it on and off? That does not seem feasible. Maybe plumb things so that the well pump pumps into a storage tank with a float switch to shut it down when full, and then a booster pump at the out port of the storage tank pumping into my existing pressure tank. Need some advice before I screw things up. Sometimes my confidence out paces my abilities and understanding. But I am always fond of a challenge.

In the past I have thought about a gravity fed storage tank in case the electricity was out for a prolonged period of time and so maybe there is a solution for both a drought situation and a power-out situation. That plan, however, was to put the gravity tank far up a hill side which would not quite work out if I plumb it as outlined above.

Suggestions?

 

[5030]

Here, our water has a ton of minerals in it, no shortage but lots of calcium so I use 3 350 gallon IBC totes for storage of rainwater from the gutters on the shop and I use that for equipment washdown and watering the garden. You could probably do the same for water storage. I did use food grade IBC totes and I wrapped each of them in black plastic stuck on with 3M general Trim adhesive so there would not be a sunlight / algae issue.

Had them for 5 years how, works very well and IBC totes are cheap to buy.

 

[LS Tractor Owner]

We had two 1750 gal storage tanks set up on our well system (when I was still using the well). Our first well went dry, drilled a second well 200' deeper. It produced 15 gal / min at first, but over 3 years, also went almost dry (maybe 10 gal per HOUR)

At that time, set up a timer in conjunction with the pump protector. When the pump protector tripped to "off", the timer would trip on, keeping the pump protector from starting the pump for 2 hours until the well would replenish. This is when we installed the tanks.

The well would feed into one tank with a float valve to turn it off when full. The second tank was just gravity fed from the first (effectively filling both tanks simultaneously). The same pipe that gravity fed the tank was where a booster pump was installed (off a "T" fitting) so it pulled from both tanks. The original 60 gal pressure tank was right after the pump, then going to the house.

It worked very well like this for years, supplying a 5 BR, 3 bath house, 6 people. ......Until that well went dry. It cost me over $35K to get the municipal water line run a mile to our house.

In your situation, I would probably just install a couple of tanks, plumb them into the system with shut off valves. You would need to put a shut off on the well pump supply line (or at least a one way check valve) to prevent the tanks from draining back down the well. Also a valve prior to the pressure tank to isolate the pressure tank to the house (This will allow shunting the well to fill the tanks without backflowing from the house). I would also put a booster pump on the tank line before the shutoff. (You can still fill the tanks just flowing backwards through the pump).

This will allow a few things...
1) if the well pump ever went out, you could still operate the household at full pressure running off the tanks.
2) you can fill the tanks from the well by turning a few valves.
3) you can run a booster pump off of a small generator, in case of power failure.
4) you can set up a hose tap after the booster to be able to connect a hose for fire suppression.... won't put out a wildfire, but could wet stuff down if needed.

I hope this helps. Don't hesitate to ask any other questions.

 

[oosik]

Have you have kept records on the static water level in your well? If so - then the first step is to see what the static water level is now. Maybe all your concern is for naught.

 

[beowulf]

LS Tractor, thank you for your thorough response. I have read it several times - understanding the concept a bit better each time. I will likely post my understanding of your plan along with questions tomorrow. I think I get most of it but not quite all. I had planned on locating the tank I was contemplating about 80 feet away and about 40 feet higher than the well, which would involve a lot of work in terms of trenching and running electricity there. But, if I understand how your plan might work for me, I think I could locate it right near the existing well and still accomplish most of my tasks. I will elaborate once I rethink all this. Thanks again - got me thinking.

 

[beowulf]

oosik, thanks for responding. The last time the well was opened the static water level was less than two feet down - that is with the pump set at about 420'. I am guessing it is about the same now. But the real problem with the wells around here would be in July - August - September. So that is what I am trying to prepare for. You are right that it may never be an issue, but if we do have a problem it would be a huge problem. One good thing, I suppose, is that we are higher than most homes here in the hills (2430' elevation) with a mountain ridge just above us. So the hydraulics of the water in the fissures in the rock might mean that we would get our water first - or could mean that it would just all drain away below us. I don't know enough about how it all works to figure out what we might face. We do have several seasonal small springs on the 90 acres.

BTW - a week ago we had a well drilled on a hill on this same property about a tenth of a mile away from our well. It is for a planned home our daughter and son-in-law want to build there. They did not hit water until 690' (8 gpm then). That well was not likely drilled in an optimal location. I should have selected a site about 300-400 feet away and near a spring but that would have been a difficult location to drill and would present significant problems with trenching and power getting there. Still, kind of wish I would have done that. I am not too old to learn things I guess.

 

[ponytug]

Judging aquifer reserves is tough in general, and especially so in California where the geology is beyond complicated. Depending on where you are, your local well company may be able to give you insights as to how large the local aquifer is, and whether you are at a deep center point or an edge. Not all drillers are happy to share that information, so definitely a YMMV.

FWIW: In our case, we are at the end of four miles or so of a ridge that has an aquifer in it, but there is no aquifer north or south of that band. My neighbor one mile west of us drilled 700' to get a low yield well. In addition to the main aquifer, there is a second small one that follows a draw. It is a much slower yielding aquifer, but lower in dissolved solids.

We use two 5,000 gallon tanks at the top of the hill fed by the main well pump. The two tanks gravity feed the rest of the property, including the house. In the house we have a 1/2HP booster into a pressure tank to have 40-60psi. Every 33.5 feet of elevation will get you 15psi.

If I were doing it over, and I will need to as the existing plastic tanks are forty plus years old, I would put in closer to 30,000 gallons of storage not so much to make it through droughts as for fire. I would also put in 12" of 2-3" rock as a base for the tanks. The current tanks have six inches or so of 1/8" minus base which the ground squirrels adore. One thing that you may want to consider is how water might get trucked to your tanks if the worst happens and your well goes dry.

@oosik makes a great point about monitoring the static water level, but I have to admit that I looked into it and it is pricey, and/or not super reliable, at least as far as I could tell. Or at least I couldn't find anything that struck me as reliable and safe. (One method is to drop a weighted string, another is to hang an air line that bubbles, neither which I want in my well, as a malfunction would likely require pulling the pump plus service.) I did find some electronic monitors, but the ones I found were thousands of dollars, for devices that concede that they aren't reliably accurate. I found a startup with an interesting solution using ultrasound probes, but they have been stuck in a verification mode for a couple of years which leads me to believe it doesn't really work.

If someone knows of a good monitor that can handle hundreds of feet in depth reliably, I am all ears.

All the best,

Peter

 

[STx]

Storage tanks are common where I am. We have one that's 9,000 gallons. The typical setup is that the well fills the storage tank using a float switch and then a booster pump supplies pressurized water from the storage tank.

I would be concerned about water just sitting in a tank asa backup getting nasty with algae and such. I think if you're going to put in the storage tank, you should go ahead and switch to a booster pump use the water from the tank.

 

[ponytug]

Storage tanks are common where I am. We have one that's 9,000 gallons. The typical setup is that the well fills the storage tank using a float switch and then a booster pump supplies pressurized water from the storage tank.

I would be concerned about water just sitting in a tank asa backup getting nasty with algae and such. I think if you're going to put in the storage tank, you should go ahead and switch to a booster pump use the water from the tank.

Unless the well water is contaminated with organic matter and bacteria, water just sitting isn't normally an issue. So, yes rain water tanks get pretty overgrown.

Our tanks are dark enough to prevent algae growing.

If you have iron or manganese in the water, letting the water sit will precipitate out some or most of the metals.

Ideally, the tanks are plumbed so that water is filled into one tank, and then flows to the next tank(s) and then is used to keep it turning over. Around here, the float is on the first tank, and the water cascades to the last tank, where the home is plumbed in near the top, with the fire line plumbed in the bottom to pull from all the tanks. Lots of ways to do it, and I think it really depends on the end users needs or goals.

All the best,

Peter

 

[5030]

All I have to say is. I'm thankful we live where we do (Great Lakes watershed). Water is never an issue here and you can hit water here with a driven point just about anywhere. Might not be the best because of the limestone strata but it's wet and plentiful.