Planning water storage for a building starts with understanding how much water its occupants use, how frequently the supply is available, and how long the stored water must last. A suitable storage plan helps property owners manage water interruptions, control project costs, and maintain reliable daily operations.
In Kenya, water storage requirements vary between residential apartments, schools, hotels, commercial buildings, farms, and industrial facilities. Each property has a different pattern of consumption, occupancy, and water availability.
This guide explains how to estimate daily water demand, calculate the required storage volume, and identify the factors to consider before planning a water storage system.
What Determines Water Storage Requirements?
The required water storage volume depends on five main factors:
- Daily water consumption: The total amount of water used by occupants, staff, visitors, or operations.
- Occupancy: The number of people regularly using the building.
- Supply reliability: How often water is supplied and how long interruptions typically last.
- Purpose of the water: Domestic use, sanitation, irrigation, industrial processes, or other activities.
- Reserve requirements: Additional water needed for unexpected interruptions or specific operational requirements.
These factors should be evaluated together. A building with fewer occupants but an unreliable supply may need more storage than a larger building with a consistent supply.
How to Calculate Daily Water Demand
Daily water demand is the starting point for estimating storage capacity.
Use the following formula:
Daily water demand = Number of users × Estimated water consumption per person
For example, consider an apartment building occupied by 40 people. If the estimated consumption is 100 litres per person per day:
40 × 100 = 4,000 litres per day.
The estimated daily demand is therefore 4,000 litres, or 4 cubic metres.
The figure of 100 litres per person is an illustrative planning assumption, not a universal requirement. Actual consumption depends on the facilities available, household habits, plumbing systems, and other uses within the building.
For commercial and industrial properties, calculate process water, cleaning water, staff consumption, and other relevant uses separately before combining them into a total daily demand estimate.
How Many Days of Water Storage Does a Building Need?
After estimating daily demand, determine how many days the property should be able to operate without a new water supply.
Use this formula:
Required usable storage = Daily water demand × Desired storage duration
For a property using 4,000 litres daily, the estimated requirements would be:
| Storage duration | Estimated usable water |
|---|---|
| 1 day | 4,000 litres |
| 2 days | 8,000 litres |
| 3 days | 12,000 litres |
| 4 days | 16,000 litres |
These figures represent usable water based on the assumed daily demand. The final tank capacity may need to be larger to account for unusable volume, operating levels, reserve requirements, and the configuration of the storage system.
The appropriate storage duration depends on the reliability of the water source, the consequences of running out of water, and the cost of providing additional storage.
Water Storage Planning for Different Types of Buildings
Water consumption patterns differ according to how a property is used. The following considerations can help establish a more accurate demand estimate.
Residential Apartments
Apartment buildings require an estimate of the number of residents rather than simply the number of units. A development with 20 occupied apartments may have very different water requirements depending on average household size.
Include water used for cooking, bathing, laundry, sanitation, cleaning, and shared facilities. Consider occupancy changes and future expansion when planning long-term storage.
Schools and Learning Institutions
Schools may require water for students, teaching staff, kitchens, sanitation, cleaning, and landscaping. Boarding schools generally have different demand patterns from day schools because students remain on the premises for longer periods.
Where occupancy varies during holidays, distinguish normal operating demand from periods of peak use.
Hotels and Hospitality Facilities
Hotels need to account for guest occupancy, staff, kitchens, laundry, cleaning, and other services. Demand may increase during busy seasons, so estimates should reflect expected peak occupancy rather than relying exclusively on annual averages.
Farms and Agricultural Projects
Agricultural water demand depends on crop type, cultivated area, irrigation method, climate, soil conditions, and livestock requirements.
Irrigation demand should be estimated separately from domestic water use. Seasonal requirements can vary substantially, making it important to consider periods of high demand and the availability of alternative water sources.
Commercial and Industrial Facilities
Commercial buildings and factories may use water for staff facilities, equipment cleaning, manufacturing processes, cooling, and other operations.
Where water is used in production, the calculation should be based on actual process requirements whenever possible. Specialised uses, including fire protection, should be assessed separately according to the applicable design requirements.
How to Select the Appropriate Tank Capacity
Once daily demand and the desired storage duration have been established, compare the calculated usable volume with practical tank options.
For example, a property with a daily demand of 4,000 litres and a two-day storage target requires 8,000 litres of usable water.
A tank with a nominal capacity of 8,000 litres may not provide the full usable volume required under every operating arrangement. The final selection should account for the tank’s operating levels and any additional reserve or technical requirements.
The selected capacity should also fit the available site, the water supply arrangement, and the property’s expected future needs.
For larger projects, storage may be divided between multiple tanks to support maintenance, operational flexibility, or different water uses. The arrangement should be planned around the project’s actual requirements rather than tank size alone.
Should the Water Tank Be Installed at Ground Level or on a Tower?
The required water storage volume and the tank’s installation height are two separate design decisions.
A ground-level tank can store water for distribution through a suitable pumping system. An elevated tank can provide gravity-fed distribution where the height and plumbing arrangement are sufficient to achieve the required pressure.
When planning an elevated installation, consider:
- The full weight of the tank and stored water.
- Structural stability and wind loading.
- Foundation capacity and ground conditions.
- Required water pressure at the points of use.
- Safe access for inspection and maintenance.
Water weighs approximately one kilogram per litre. Consequently, 10,000 litres of stored water alone weighs approximately 10,000 kilograms, or 10 tonnes, excluding the tank and supporting structure.
Elevated installations must therefore be assessed and designed by appropriately qualified professionals. Tank capacity should never be used as the sole basis for selecting a tower or foundation.
Other Factors to Consider Before Finalising Your Storage Plan
Water Quality
Water intended for drinking or food preparation must be stored in a suitable tank with appropriate materials and protective coatings. The design should minimise contamination risks and allow cleaning and inspection.
Available Space
The installation area must accommodate the tank, access for maintenance, plumbing connections, and any supporting structure. Delivery and installation access should also be considered.
Corrosion Protection
Steel storage systems require appropriate corrosion protection for their intended environment and water use. The protective system, inspection arrangements, and maintenance requirements should be considered during project planning.
Future Expansion
A building may experience increased occupancy, additional production, or changes in water demand over time. Allowing for realistic future requirements can help avoid costly alterations later.
Separate Operational Reserves
Some projects have specialised water requirements, such as emergency or firefighting reserves. These should not automatically be included in ordinary domestic storage calculations; they must be evaluated according to the relevant project requirements and applicable regulations.
Plan Your Water Storage Project With Steel Water Tanks Kenya
Accurate water demand estimates provide a practical starting point for choosing a storage solution. By considering occupancy, daily consumption, supply interruptions, installation conditions, and future requirements, property owners can make more informed project decisions.
Steel Water Tanks Kenya works with customers planning water storage for residential, agricultural, commercial, institutional, and industrial applications.
If you are planning a new development or upgrading an existing water storage system, contact our team to discuss your requirements.
Email: sales@steelwatertankskenya.co.ke
Phone: +254 714 138898
Share your property type, estimated daily water demand, location, and preferred storage duration to help us understand your project.
Reliable water storage planning begins with knowing your water requirements.
