CEB Water Cistern

I have considered a brick cistern many times, but I worry about the tension stresses over time. Of course, that will depend on how much water and how big you will make it.

If you keep it under 5 foot tall, the stresses are minimal at the bottom, no matter the diameter. I saw several designs where people used metal strapping on the outside every other course or so as a reinforcement for the bricks.

Definitely go stabilized, and then on the inside, do a thin (1/4") cement stucco (1:1 cement to VERY FINE sand), then do a thinner coat (1/8") of pure cement and water (you could add lime or acyrlic here as well) and then finish it off with one or two coats (1/8" each) of Thoroseal, or another acrylic concrete sealer.

I am hoping to do a 8000 gallon cistern in May, but I will be pouring concrete in forms. It will be reinforced a lot, but as far as time and cost are concerned, poured concrete (4-6" thick) is the cheapest way to go, especially if you are going to make more than one (cost of forms gets spread out over several cisterns).

For the floor, you'll still have to do a slab, and don't skimp on reinforcement.

If built right, ferrocement tanks can have a lifespan of more than 100 years, and I don't see why reinforced concrete or a properly reinforced CEB tank would be different.

One side note on masonry tanks - never let them dry out. They should always have a bit of water to maintain humidity and avoid major cracking.