Demand for water determines the capacity of the system. This system has been sized for an LGU of 100,000. The parameters used for calculating the total demand is shown in Table 3-19.
Table 3-19: Design Parameters
| Item | Quantity | Unit |
| Present Population | 100,000 | persons |
| Domestic Demand | 100 | 1pcd |
| Average Daily Domestic Demand | 10,000 | m3/day |
| Institutional Demand (20% of Domestic) | 2,000 | m3/day |
| Commercial Demand | 2,000 | m3/day |
| Unaccounted for Water (10% of Domestic) | 1,000 | m3/day |
| Total system Demand | 14,500 | m3/day |
| Future (10 years) Demand (25% of Domestic) | 17,500 | m3/day |