Is drinking water from a plastic holding tank safe?

As most of you know I am building a home and am contemplating using an existing well on our property to serve the domestic needs of our house. If we go this route we will need to use one or two 5,000 gal plastic tanks to store the water due to the low gpm output on the exsiting horizontal well.

My wife is very concerned about this as the stored water has the potential to become stagnant, grow bacteria, become warm from the sun, etc.

Do any of you have experience with this type of holding tank scenario?
Has anyone had problems with this scenario?
Anyone have suggestions and/or pitfalls to look out for when going this route?

witch said:

What is your low output well capable of producing?

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~ 10-15 gpm

witch said:

Buy a Black tank, the water won't get hot.

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How is that when black absorbs all wavelengths of sunlight, as opposed to a white tank which would reflect a large portion of the sun's rays?

All "cistern" type tanks require periodic cleaning and sanitizing and more frequently depending on the water quality you put in them. Iron and manganese along with nonharmful bacteria and any introduced bacteria, bugs or airborne can cause rust, particulate matter and odor problems.

You will have to be able to physically get into the tank to clean/disinfect/sanitize it properly. Working in confined space cautions should be taken, especially if using strong disinfectants like chlorine.

Unless the cistern is fully buried, and you need to be very careful in burying any plastic tank, the air temp alone will warm the water. The more water in the tank the warmer it will be. Black is the best choice of color.

How much storage is in this 10-15 gpm horizontal well?

witch said:

Is your pump running out of water?

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No, it is a horizontal well that flows under gravity (i.e. free water!). We will have very large slope areas to irrigate daily so we will at least need one 5K tank and a booster pump/bladder tank setup.

This pump/tank combo will provide pressure to our home as well.

witch said:

You don't want a white (natural) tank, you will get all kinds of algae growth. A black tank will sink it's gained heat to the ground, and radiate it's heat to the North side of the tank, you're also cycling the water in the tank with more cool water from the well, also the water from the tank will usually go thru several hundred feet of buried PVC to get to the house. Trust me it won't get hot.

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Ah, makes sense...We will likely sink the tank partially in the ground to lower its profile anyway so that will help with the heat too I assume.

Gary Slusser said:

How much storage is in this 10-15 gpm horizontal well?

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If I can still do my distribution math correctly it has approx 80 gallon capacity.
(pi*r^2*L*7.48) = (3.14*.08^2*500*7.48) = ~80 gals.
2" diameter
500 feet long

riverside67 said:

... it is a horizontal well that flows under gravity (i.e. free water!). We will have very large slope areas to irrigate daily so we will at least need one 5K tank and a booster pump/bladder tank setup.

This pump/tank combo will provide pressure to our home as well.

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If you place the pump at the end of the well line and *after* a tee going off to the storage tank (rather than pumping directly from the tank), then the water pumped to the house while no irrigating is going on will come from the well rather than from the tank ... and with a little more thought, I bet there is a way to keep water from the tank from ever going to the house.

It's possible that our home would have a domestic demands of >10 gpm at one time especially if multiple showers were running while the clothes and dishwasher were running at the same time.

If the house demand was greater than the output of the well the inlet of the pump would not remain flooded, hence the need to pump from the tank to the house.

riverside67 said:

It's possible that our home would have a domestic demands of >10 gpm at one time especially if multiple showers were running while the clothes and dishwasher were running at the same time.

If the house demand was greater than the output of the well the inlet of the pump would not remain flooded, hence the need to pump from the tank to the house.

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No, the pump would always have plenty of water, but the water in the tank would only go to the house when/if the demand at the house became greater than the output of the well.

riverside67 said:

It's possible that our home would have a domestic demands of >10 gpm at one time especially if multiple showers were running while the clothes and dishwasher were running at the same time.

If the house demand was greater than the output of the well the inlet of the pump would not remain flooded, hence the need to pump from the tank to the house.

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You may be over cautious, a larger amount of homes do not have a flow rates greater than 10 gpm.

99k said:

You may be over cautious, a larger amount of homes do not have a flow rates greater than 10 gpm.

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And yet more and more homes today have large tubs and two person showers with or without body sprays. Some big tubs alone flow at close to 10 gpm, and for 15 minutes+ while filling. Add a toilet flush and they are over 10 gpm. Add laundry or dishwashers and a shower and many are over 15-16 gpm. I've recently sold a softener to a 45 yo widower customer in FL living alone with a shower running at 22 gpm alone. He uses it 1-2 times a day. And he hopes to eventually meet someone and has a large tub too.

I sell to many water treatment customers that have max flow rates of 12-13 gpm flow rates.

Gary Slusser said:

And yet more and more homes today have large tubs and two person showers with or without body sprays. Some big tubs alone flow at close to 10 gpm, and for 15 minutes+ while filling. Add a toilet flush and they are over 10 gpm. Add laundry or dishwashers and a shower and many are over 15-16 gpm.

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Our home will have these types of demands at certain times.