Water Tank Construction
Types, steps, and cost for water tanks. El-Eman Office builds concrete water tanks with guaranteed waterproofing.
Sizing the tank for the building's needs
Before building a water tank, its volume must be worked out from the number of users, the type of building and the expected hours of water cut. A small tank means the water runs out quickly, while a very large tank means water stays stagnant and its quality declines, and it costs more in space and construction. In large buildings a separate capacity for firefighting is sometimes calculated. The location is chosen so that connection to the pumps and network is easy, so that it is away from sources of contamination such as sewer lines, and so that it can be reached for maintenance.
Waterproofing and testing make a sound tank
The most common problems with concrete tanks are leaks and damp. Care is therefore taken to design the concrete with suitable proportions and admixtures that reduce permeability, and to cast the walls with the floor using carefully planned joints, because a cold joint between two pours is the weakest point. Waterproofing materials suitable specifically for drinking water, with a certificate of suitability, are used. After construction, the tank is filled for a set period and the water level is watched to detect any loss before the sides are backfilled or finished.
- Inspect and treat cracks and voids before waterproofing.
- External waterproofing on underground tanks to stop groundwater entering or water leaking out.
- Ventilation and cleaning openings with a tight cover that keeps out dust and insects.
- A fall in the tank floor toward a drain point to make cleaning easier.
Safety and operation
An underground tank is affected by soil and groundwater: if the groundwater level is high, buoyancy may act on the empty tank, and the design must allow for it. An elevated tank adds concentrated loads on the structure and needs its own structural design. For operation, level gauges, valves and easily reachable connections are needed, along with a regular cleaning schedule. Drinking water should be kept separate from irrigation or firefighting water.
- Calculate the required capacity and choose a suitable site.
- Investigate the soil and groundwater level before design.
- Carry out casting and waterproofing in the correct sequence and test for leaks.
- Set a plan for regular cleaning and maintenance.
Materials and health requirements
Tank materials come into direct contact with water, so they must be suitable for contact with drinking water as the specifications require. Paints and waterproofing that leave no taste, odour or harmful substances are preferred, and a sufficient period of airing and washing before commissioning is advised. The tank should also be tightly covered and fitted with vents protected by mesh. Openings are cleaned and disinfected before first use and after any maintenance work, with periodic checks of water quality, especially in residential buildings and public facilities.
Frequently asked questions
How often should a tank be cleaned?
It is cleaned periodically according to water quality and local conditions. Health authorities recommend specific schedules, but the key is not to neglect inspection.
Is a polyethylene tank a suitable alternative?
It suits small and medium capacities and installs quickly, but for large capacities concrete is usually preferred.
Why does water appear around an underground tank?
It may be a leak from the tank itself or groundwater rising around it. The two are told apart by a water-loss test and by watching the level.
