Water tank size questions & answers:

This article answers common questions about how to choose or specify the required size for a water pressure tank or water storage tank.

This article series answers just about any question you may have about pumps, wells, and drinking water.

Water Tank Sizing FAQs

Question: ran out of water after filling up the swimming pool

(June 21, 2012) Brody said:

This sounds like our problem. We filled up a small pool yesterday, with filtered and softened water. Ever since then we have not had enough water to take a shower or do the laundry, but when I go and shut off the main valve and turn it back on we have water gain for a short while. So what do I do just wait it out and allow it to fill up?

Reply:

Brody: WOW. Filling a pool with filtered softened water - expensive, and certainly exhausted your water softener's salt charge as well as, apparently, your well. Your well will probably recover if you wait - it may take several hours or longer. Many residential wells do not have the flow rate and capacity to fill swimming pools.

If you still have no water after 3-6 hours, I'd begin to worry that your long water run may have damaged a pump or pump control.

(Oct 23, 2012) Shawn said:

Regarding the filling of the pool with well water: The most common cause of well failure is overpumping.

Did you notice sand or silt in the water?

You may have "eroded" the aquifer pulling in fines and plugging the pores of the aquifer and slots or holes in the casing or liner. Other problems can be caused as well such as precipitation of chemicals (iron. etc. - can occur fairly quickly) and increased biofouling (this is longer term though).

The rate at which the water flows into the well may be permanently decreased now.

Sometimes rehabilitation (by a well driller) may help but may not be possible.

Question: how to calculate water tank volume in gallons

how much water does a 56 IN BY 26IN BY 17 IN TANK HOLD

Reply:

Anon: calculate the water tank volume in cubic inches and multiply that by 0.004329 to get the volume in gallons

Question: water tank drawdown amounts

(July 30, 2015) Southern Girl said:
how many gallons of water should be used before the plum start again in a 86 gallon tank? my 86 gallon tank would re-pump after 9 gallon water usage, does that mean it is short cycled?

Reply:

Typically you should see 30 seconds to a minute of running water at a single sink tap before the pump turns on. I suspect your tank is waterlogged. Search InspecApedia for "WATER TANK AIR, HOW TO ADD" for details.

The volume of water drawn down will vary depending on the system operating pressure range, pipe sizes, and plumbing fixture flow rates. Typically at a kitchen sink tap I might see 3-7 gpm, so you should certainly see several minutes of draw-down before the pump cuts on IF you start with the tank full - that is, right at the end of a pump cycle when the pump has just shut off.

Other causes of short cycling are at WATER PUMP SHORT CYCLING

Also see AIR VOLUME CONTROLS, WATER TANK

Question: Artesian well flow rate numbers

(Aug 16, 2015) Sunny Stapelman said:
We have an artesian well that is pumped into a 1000 gallon cistern which is then pumped into our home. When considering the GPM, is it from the well or the cistern? Our well is suppose to produce 3.5 GPM. Is that what prospective buyers should be concern with or is it the GPM from the cistern?

Reply:

Thanks for the excellent question, Sunny.

A home buyer as well as some lenders are concerned with the how much water can be obtained from the well - a flow rate, usually measured over 24 hours. That's the 3.5 gpm according to your data.

When a well has a modest flow rate, to assure that the building occupants don't run out of water during normal daily use, people install a larger holding tank or cistern - that's your 1000g cistern.

The pump that is used to deliver cistern water to the home is what gives good water pressure in the house. It has nothing to do with the well.

Question: how to improve drawdown cycle

(May 29, 2016) Dave said:
I have a 33 gal Red lion water tank & a 3/4 hp red lion submersible pump water cut in 42 psi out 62 psi
Tank air is 40 psi
My draw down between cycles is only 5 gallons.
How do I improve it ?

Reply:

Check that the tank is not waterlogged, dave. Or search InspectApedia for

WATER TANK AIR HOW MUCH TO ADD

Question: Gould Hydro Pressure tank is waterlogged

(Aug 15, 2016) Titan Croteau said:
I had two 85 gallon gould hydro pressure tanks one of them is water logged can I just use one of them funds are limited for a 200 s square foot home

Reply:

Yes you can. Your pump will cycle twice as often.

See WATER TANK AIR, HOW TO ADD

Question: too much pressure causing pressure switch to cycle on and off too quickly?

(Sept 22, 2016) lynn said:
I have to much pressure which causes the pressure switch to cycle on an off very quickly

Reply:

This doesn't sound right to me, Lynn. But you can certainly try partly losing a supply valve below the "too much pressure" fixture. Keep in mind you're not adjusting absolute water pressure, you're reducing the flow rate in gallons per minute.

[Click to enlarge any image]

Article Series Contents

• WATER TANK SIZE & VOLUME
  • CALCULATE ACTUAL WATER TANK VOLUME
  • ACTUAL WATER TANK DRAW-DOWN VOLUME
  • WATER TANK SIZING CHARTS
• WATER TANK SIZE & VOLUME FAQs

...

Continue reading at WATER TANK SIZE & VOLUME or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• EXPANSION TANK SIZING GUIDE - tank sizing tables for expansion tanks used on hot water heating systems
• LARGE CAPACITY WATER STORAGE TANKS
• ROOFTOP WATER TANKS
• PLASTIC RECYCLING CODES, TANKS, TYPES where we describe health and other concerns involving plastic tanks and other containers used for water storage.
• WATER QUANTITY IMPROVEMENT
• WATER TANK RELATION to WATER PRESSURE
• WELL YIELD IMPROVEMENT
• WATER TANK DIAGNOSIS & REPAIR - home or see WATER TANK REPAIR PROCEDURES

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at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER SUPPLY, PUMPS TANKS WELLS & SPRINGS

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