California Concrete Water Tank Storage Systems


Quality Construction since 1984



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Water Tank Comparisons



Poly (plastic) rainwater tanks

Poly tanks are made from polyethylene; a UV stabilized, food grade plastic. The tanks are light, you only need a sand base to place them on, they come in a wide variety of colors and have a long serviceable life. Many poly tanks carrying a 25 year warranty, although many claim 15 years is a very realistic lifespan. They are also usually the second cheapest of the options covered in this article.

One of the major disadvantages of polyethylene is the material is made from petrochemicals. Even after their serviceable life has ended, there's still a great big hunk of plastic that will take generations to break down and will release toxins as it does so.

However, polyethylene tanks can still be easily recycled after 15 years, so it's just a matter of breaking the tank up and then carting it away rather than trying to squeeze a few more years out of one.

Some poly tanks are made with a vertical seam - this is a weak point that may cause splitting and subsequent water loss. Polyethylene water tanks and fire don't really mix either - they'll just melt. This can be a real problem if you're in a rural area and you need that water to fight a fire.

The other issue is the long term effects of drinking water stored for such a long time in this material. Polyethylene tanks are relatively new on the market, it is not known if  there are any credible serviceable life studies that have been done in relation to these issues. 

Some people do note a bit of an odd taste to the water if the tank is placed in full sun.

Just on that point - before purchasing a poly tank, check the warranty for temperature stipulations as some manufacturers will void the warranty if conditions where the tank is installed can get extremely hot.

Steel tanks

Galvanized tanks have been around for over 150 years and are usually the cheapest type of tank. Hot-dip galvanizing is a process used to coat steel or iron with zinc. The Zinc helps slow down corrosion, but depending on environmental factors, a galvanized tank may last well under 5 years. This is due to electrolysis.

Some metal tanks now also have polyethylene linings to further help retard corrosion - escaping plastic altogether can be a difficult thing to do these days.

With  a steel based tank, seriously consider the composition of the water you are storing and its potential to accelerate corrosion in any exposed metals.


This is another long-lasting option that can be installed above or below ground. Fiberglass tanks resist corrosion and are not generally affected by chemicals.

As fiberglass tanks tend to allow more light in than other types of tank materials, this can encourage the growth of algae, so they should be painted. Fiberglass can also tend to be brittle, leaving it prone to cracks - something you don't want, particularly in an in-ground situation.

Concrete water tanks

Concrete water storage tanks can be built above grade or mostly hidden from view.  They are built on site because  of the material’s weight.  Concrete is a porous material and needs to be sealed to prevent minerals leaching into the water.  With proper sealing and construction techniques, this is can be addressed. 


Mining production and delivery of concrete is energy intensive.  The advantage is achieved by its long life and its ability to be simply recycled. 

Choosing a tank material

Choice is wonderful, but as you can see, there's advantages and disadvantages with each type of tank, particularly when it comes to environmental impact - so it's really a matter of gaging your needs and budget and then choosing the lesser of the evils. In regards to the financial side of things, bear in mind not just the initial cost, but how many times the tank will need replacing over X years. This also plays a role in the amount of resources used



For further information contact:

Northern and Central California
John T. Bodine
General Engineering, Building and Electrical Contracting
License #422643
Cell 805 -459-7204

Southern California
Roger  A. Ellestad
Ellestad Builders, Ltd.
License #529284
Cell 951-757-2271 
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