We have installed a lot of underground water tanks over the years. You name it, we've installed it. Some systems we like, and others... well...
We try to be as objective as possible with all of our assessments of rain systems and system components. In the interest of full disclosure, we sell our own line of precast concrete tanks. But we don't hype up concrete tanks to make a sale. Quite the contrary — we sell concrete tanks because, when cast with high standards, they are hands down the best water storage option available. Don't believe us? Keep in mind that we also sell plastic underground cisterns, but we rarely recommend them even though they are more expensive per gallon. See our Underground Plastic Cisterns: Pros and Cons article for more information.
In our experience, these are the pros and cons of precast concrete tanks.
Advantages
- Long life. We've cleaned out 50+ year-old concrete tanks that are still as good as new.
- Functional. Unlike plastic tanks, you can drive a mower across a concrete tank without concern.
- Easily repairable. If the tank is cast correctly, you'll never have to replace it.
- Load-bearing capabilities. Concrete tanks can be made to support traffic loads — they can go under driveways or parking lots.
- Improved water quality. Concrete walls tend to neutralize rainwater's acidity for a more balanced pH.
- Inexpensive. Concrete systems are usually the least expensive option per gallon.
- Accessible and cleanable. Unlike plastic tanks, concrete tanks can be pumped completely dry for cleaning.
- Recyclable. If necessary, concrete tanks can be broken up and taken to a recycling facility where the concrete is pulverized into fill material.
Disadvantages
- Heavy equipment required. You must have good site access to set a concrete tank — this cannot be overstated.
- Limited availability. Precast concrete cisterns are not widely available in the U.S. Go with a vendor that specializes in them — don't just adapt a septic tank for your application.
- Resource-intensive. Concrete — and Portland cement in particular — has a high carbon footprint.
- pH effect of new concrete. Generally, you should not drink water from the first three fill/empty cycles of a new concrete tank, as new concrete will initially elevate pH. After that, water pH neutralizes quickly. For more information, see our article on Concrete Cistern pH.
Summary
When installed correctly, precast concrete cisterns are the most durable, cost-effective, and water-quality-friendly underground storage option available. They outlast plastic, support heavy loads, and can be cleaned and repaired indefinitely. The main trade-offs are the need for heavy equipment during installation and limited regional availability. If you have good site access and want a tank that will last generations, concrete is the right choice.
Have questions about whether a concrete cistern is right for your property? Call or text us at (937) 949-1100 — we're happy to talk through your project and point you in the right direction.
