Skip to content
ENExplore Calculators

Reservoir Storage Capacity Calculator

Work out reservoir storage capacity instantly with clear inputs, formula shown and shareable results.

About Reservoir Storage Capacity Calculator

Service reservoir storage has three components: balancing storage to absorb the difference between steady supply and variable demand, typically a third to a half of daily demand; a fire-fighting reserve set by the required flow and duration; and an emergency reserve for supply interruption.

Formula

Storage capacity

Total = average daily demand x (balancing days + emergency days) + fire reserve

Worked example

With the default values below, Reservoir Storage Capacity Calculator returns Total Storage Required of 13,150.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Average Daily Demandminimum 0 m3/day
8,500 m3/day
Balancing Storageminimum 0 days
0.5 days
Fire Reserveminimum 0 m3
400 m3
Emergency Reserveminimum 0 days
1 days

Results

Total Storage Required
13,150.00
Balancing Storage
4,250.00
Emergency Storage
8,500.00
Days Of Storage
1.5471

Step by step

  1. 1Values used
  2. 2Storage capacity
  3. 3Total Storage Required= 13,150.00
  4. 4Balancing Storage= 4,250.00
  5. 5Emergency Storage= 8,500.00
  6. 6Days Of Storage= 1.5471

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Fire-fighting storage and flow requirements are set by the fire authority and building regulations. Confirm requirements before finalising reservoir capacity.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Fire-fighting storage and flow requirements are set by the fire authority and building regulations. Confirm requirements before finalising reservoir capacity.

Frequently Asked Questions

Can storage be too large?

Yes. Excess storage lengthens water age, allowing chlorine residual to decay and disinfection by-products, nitrification and taste problems to develop. Turnover should be at least once every few days.

How is fire reserve determined?

From the required fire flow for the largest risk in the zone and the duration the fire authority specifies — commonly 30 litres per second for two hours in residential areas, far more for industrial risks.

Related Calculators

Reservoir Storage Capacity Calculator | Calcrivo