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I'm about to place a water storing tank at ground level and connect the water feeder pipe at the bottom of the tank. Would water fill normally as the top filling? Would atmospheric pressure + water mass pressure cause water feed pipe to stop following water?

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    It would only fill until the pressure of the water column in the tank was equal to the pressure of the feed pipe. – Comintern Nov 25 '16 at 14:33
  • Is this tank outside? What is the volume of this tank and will it be pressurized by a pump? Where is the outflow to be located? Is this potable water or water for irrigation? – Jim Stewart Nov 25 '16 at 17:09
  • @JimStewart Yes. This would be placed outside. Tank volume would be 500 Litres. And nope, water will not pressurized by a pump. It would be just an outlet from the city water supply, which in my area is less pressure. That's the soled purpose of having this ground tank. – inckka Nov 28 '16 at 7:49
  • @Comintern Is there anyway to measure the column pressure? My feed pipe is 0.5 inch in diameter. – inckka Nov 28 '16 at 7:50
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    If the pressure is enough to fill the tank from the bottom, it is also enough to feed it from the top. Either way, you need to get water to the height of the tank. If normal pressure can deliver water to the upper floors of a house, it ought to be able to reach the top of a tank at ground level. – fixer1234 May 5 '17 at 7:34
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If the pressure in the supply water line can force water up the outside of the tank and over the top, above the tank water level, then that same pressure can do what you want: force the water directly into the bottom of the tank against the same pressure head.

The problem is that, by making the direct connection at the bottom of the tank, you have no way of preventing a backflow of water from the tank, if the supply pressure drops below the pressure in the tank. If this backflow is into a city water supply, then this is a major safety hazard, and forbidden by most codes...

  • A check valve would solve that problem. – Connor Bredin Nov 25 '16 at 23:23
  • @DJohnM I was trying to make it bottom fill due to the water pressure is very low. I was thinking either I have to keep the tank ground level and fill from the bottom or bury the tank underground and fill from top. So as per your answer the later method seems correct I guess. – inckka Nov 28 '16 at 8:00
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Yes you can. Feeding the tank from above will exert the constant maximum head on the pump until the tank is full. Feeding from bottom leads to uniform increase of head from zero to maximum head. Also, feeding from the bottom will cut the energy consumption and time by half if the same capacity pump is used (I think). You can prevent the backflow by putting a NRV in line.

  • My initial purpose was to connect urban water supply feed (which is very low pressure) to the tank and I wondered, since the water pressure is very low but constant in the ground level, either feed it to bottom of the tank or bury the tank underground and feed it from top. Anyhow as per the answers it seems both methods are same and I'd need to use a pump to get some pressure. However the NRV is a new thing for me. Thanks for mentioning that. – inckka Jul 6 '17 at 2:16

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