Water Storage Backup System - Tips

W@P

W@P

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Yes, another thread on a water backup system.
I am adding an extra tank to supplement my current 950L muni water tank. Not interested in the legalities of having muni water storage. They can jump off a cliff.

I currently have a 950L tank that feeds from the incoming water line from muni side with a float valve to shut off the water inflow when the tank is full. This is then connected to a pressure booster pump to feed the house when needed.

Which option would be best:
  1. Would adding the second tank be as simple as connecting the bottom outlets of both tanks with a T-piece which then runs to the pump intake? My thinking is that having the ball float valve in only one tank, it will start filling tank 1 and water will move towards tank 2 via the 2 outlet connections of both tanks that are connected in the same line before the pump and float valve will shut off when both tank 1 and 2 are at the same level. This obviously means that when using the tank water, water will be sucked from both tanks by the pump, but refilling while using the pump will only be done in tank 1 until the pump stops and water can start flowing to tank 2 through the outlet line.
  2. Or, would I need to add a float valve on tank 2 as well? So both fill with water coming from muni side and stop when they are full. Outlets are then still connected with a T-piece before pump intake so water will be sucked from both tanks while the pump is running.
There will be a ball valve on both tank 1 and 2 outlets to isolate one or the other should I need to.

Any advice will be appreciated.

I found a pic of this setup and that is exactly what I had in mind.

1712289710274.png
 
Option 1 is correct as long as both tanks are identical.
 
bwana said:
Option 1 is correct as long as both tanks are identical.
Click to expand...
Yes if they were identical and placed on the same level there should be no problems.

In my case, tank 1 has a height of 1970mm and tank 2 has a height of 1920. The inlet port on both tanks are situated a few mm from the very top of the tank obviously.

So let's say tank 1 inlet port is at 1850mm and tank 2 inlet port is at 1800mm. Assuming they stand on the same level surface one could manipulate the float valve in tank1 to such a level that suits shut off that is at an acceptable level for both tanks. Right ?
 
W@P said:
Yes if they were identical and placed on the same level there should be no problems.

In my case, tank 1 has a height of 1970mm and tank 2 has a height of 1920. The inlet port on both tanks are situated a few mm from the very top of the tank obviously.

So let's say tank 1 inlet port is at 1850mm and tank 2 inlet port is at 1800mm. Assuming they stand on the same level surface one could manipulate the float valve in tank1 to such a level that suits shut off that is at an acceptable level for both tanks. Right ?
Click to expand...
I have four 1890lt tanks, almost level to each.

Not sure about your scenario, but it is plausible provided they close enough in size to each other.

Since I did not know what I was doing, I connected all four at the bottom via T connection. My float switch, is used to top up the tanks from the well point pump.

The top holes, I seal off with the supplied plastic taps. Never had an issue since Dec 2017.
 
W@P said:
Yes if they were identical and placed on the same level there should be no problems.

In my case, tank 1 has a height of 1970mm and tank 2 has a height of 1920. The inlet port on both tanks are situated a few mm from the very top of the tank obviously.

So let's say tank 1 inlet port is at 1850mm and tank 2 inlet port is at 1800mm. Assuming they stand on the same level surface one could manipulate the float valve in tank1 to such a level that suits shut off that is at an acceptable level for both tanks. Right ?
Click to expand...

As long as the float valve in tank one is below both top outlets of both tanks you will be fine. The sizes shapes hights etc wont matter you just need to make sure of that and then of course join the 2 tanks at the bottom.
 
RonSwanson said:
Why? The water in both tanks will equalise to the exact same level regardless of tank size.
Click to expand...
Exactly. If he gets a squatter second tank it’s going to continuously overflow and the float valve will never close and if he gets a taller tank it will never fill to capacity.
 
bwana said:
Exactly. If he gets a squatter second tank it’s going to continuously overflow and the float valve will never close and if he gets a taller tank it will never fill to capacity.
Click to expand...
Shorter and taller tanks, yes. But the tanks can be fatter or thinner.

Edit: And if he makes use of the ball valves at the bottom, he could store water in one tank at a higher or lower level than the other. A PITA to manage I agree, but possible.
 
Thank everyone. I got it.
 
Update:

Installed the second tank. Piping a fscking maze atm. It looks deurmekaar but everything works. Maybe one day I will redo everything nice and neat.

1713182441408.png
1713182503257.png
 
W@P said:
Yes, another thread on a water backup system.
I am adding an extra tank to supplement my current 950L muni water tank. Not interested in the legalities of having muni water storage. They can jump off a cliff.

I currently have a 950L tank that feeds from the incoming water line from muni side with a float valve to shut off the water inflow when the tank is full. This is then connected to a pressure booster pump to feed the house when needed.

Which option would be best:
  1. Would adding the second tank be as simple as connecting the bottom outlets of both tanks with a T-piece which then runs to the pump intake? My thinking is that having the ball float valve in only one tank, it will start filling tank 1 and water will move towards tank 2 via the 2 outlet connections of both tanks that are connected in the same line before the pump and float valve will shut off when both tank 1 and 2 are at the same level. This obviously means that when using the tank water, water will be sucked from both tanks by the pump, but refilling while using the pump will only be done in tank 1 until the pump stops and water can start flowing to tank 2 through the outlet line.
  2. Or, would I need to add a float valve on tank 2 as well? So both fill with water coming from muni side and stop when they are full. Outlets are then still connected with a T-piece before pump intake so water will be sucked from both tanks while the pump is running.
There will be a ball valve on both tank 1 and 2 outlets to isolate one or the other should I need to.

Any advice will be appreciated.

I found a pic of this setup and that is exactly what I had in mind.

View attachment 1686379
Click to expand...
Just a thought on solution 1 - if you're going to want to isolate your tanks (eg 1st tank springs a leak/dirty/whatever) you won't be able to fill up the 2nd tank.
 
W@P said:
Ja no definitely not ideal but it is what it is hahahaha.
Click to expand...
Not being critical - you should see my setup. My entire house can be run off a garden hose :)
 
Sinbad said:
Just a thought on solution 1 - if you're going to want to isolate your tanks (eg 1st tank springs a leak/dirty/whatever) you won't be able to fill up the 2nd tank.
Click to expand...
It's a lesser of two evils thing. With two ball valves, you'd have to get them to stop at exactly the same height, else one will stop, the other one still goes a bit, still filling the slightly lower tank until equilibrium is reached. Having two ball valves on the same line going at the same time within a short distance from one another, has a resonance (squealing) potential. Ultimately, piping is so mechano set'ish, it would not be worthwhile pursuing full redundancy if you're slightly handy (seems so - in fact artistic - LOL).

KISS principle.

Essential is a valve at the bottom of each, before the pump (which I see the OP has).

/My 5c :)
 
W@P said:
Update:

Installed the second tank. Piping a fscking maze atm. It looks deurmekaar but everything works. Maybe one day I will redo everything nice and neat.

View attachment 1691517
View attachment 1691523
Click to expand...
jislaaik, that is very busy.

If you are going to redo, plan it out.

I prefer pvc welding as much as possible, as you can get a much neater look.
 
rh1 said:
jislaaik, that is very busy.

If you are going to redo, plan it out.

I prefer pvc welding as much as possible, as you can get a much neater look.
Click to expand...
Very busy indeed. Will have to redo it some time and plan it out nicely.
 
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