Domestic and Non-domestic Needs
Domestic and non-domestic needs
The recommended values for domestic and non-domestic purposes are given in Table 2.1.
| Sl. No. | Classification of towns/cities | Recommended maximum water supply level (lpcd) |
|---|---|---|
| 1 | Towns provided with piped water supply but without sewerage system | 70 |
| 2 | Cities provided with piped water supply where sewerage system is existing or contemplated | 135 |
| 3 | Metropolitan and mega cities provided with piped water supply where sewerage system is existing or contemplated | 150 |
Notes:
- In urban areas, where water is provided through public standposts, 40 lpcd should be considered.
- Figures exclude “Unaccounted for Water (UFW)”, which should be limited to 15%.
- Figures include requirements of water for commercial, institutional and minor industries. However, the bulk supply to such establishments should be assessed separately with proper justification.
Institutional needs
The water requirements for institutions should be provided in addition to the provisions indicated above, where required, if they are of considerable magnitude and not covered in the provisions already made. The individual requirements would be as follows:
| Sl. No. | Institution | Litres per head per day |
|---|---|---|
| 1 | Hospital (including laundry): (a) number of beds exceeding 100 (b) number of beds not exceeding 100 | 450 (per bed) 340 (per bed) |
| 2 | Hotels | 180 (per bed) |
| 3 | Hostels | 135 |
| 4 | Nurses’ homes and medical quarters | 135 |
| 5 | Boarding schools/colleges | 135 |
| 6 | Restaurants | 70 (per seat) |
| 7 | Airports and seaports | 70 |
| 8 | Junction stations and intermediate stations where mail or express stoppage (both railway and bus stations) is provided | 70 |
| 9 | Terminal stations | 45 |
| 10 | Intermediate stations (excluding mail and express stops) | 45 (could be reduced to 25 where bathing facilities are not provided) |
| 11 | Day schools/colleges | 45 |
| 12 | Offices | 45 |
| 13 | Factories | 45 (could be reduced to 30 where no bathrooms are provided) |
| 14 | Cinemas, concert halls and theatres | 15 |
Fire fighting demand
It is usual to provide for fire fighting demand as a coincident draft on the distribution system along with the normal supply to the consumers. A provision in kilolitres per day based on the formula 100√p, where p = population in thousands, may be adopted for communities larger than 50,000. It is desirable that one third of the fire fighting requirement forms part of the service storage. The balance requirement may be distributed in several static tanks at strategic points. These static tanks may be filled from nearby ponds, streams or canals by water tankers wherever feasible. High-rise buildings should be provided with adequate fire storage from the protected water supply distribution.
Industrial needs
While the per capita rates of supply recommended will ordinarily include the requirement of small industries (other than factories) distributed within a town, separate provisions will have to be included for meeting the demands likely to be made by specific industries within the urban areas. The forecast of this demand will be based on the nature and magnitude of each such industry and the quantity of water required per unit of production. The potential for industrial expansion should be carefully investigated, so that the availability of adequate water supply may attract such industries and add to the economic prosperity of the community.
As can be seen from the table, the quantities of water used by industry vary widely. They are also affected by many factors such as the cost and availability of water, waste disposal problems, management and the types of processes involved. Individual studies of the water requirement of a specific industry should be made for each location, the values given below serving only as guidelines. With the reuse of water in several industries, the requirement of fresh water is being reduced considerably.
| Industry | Unit of production | Water requirement (kilolitres per unit) |
|---|---|---|
| Automobile | Vehicle | 40 |
| Distillery | Kilolitre of alcohol | 122–170 |
| Fertilizer | Tonne | 80–200 |
| Leather | 100 kg (tanned) | 4 |
| Paper | Tonne | 200–400 |
| Special quality paper | Tonne | 400–1000 |
| Straw board | Tonne | 75–100 |
| Petroleum refinery | Tonne (crude) | 1–2 |
| Steel | Tonne | 200–2580 |
| Sugar | Tonne (cane crushed) | 1–2 |
| Textile | 100 kg (goods) | 8–14 |
Pressure requirements
Piped water supplies should be designed on a continuous 24-hour basis to distribute water to consumers at adequate pressure at all points. Intermittent supplies are neither desirable from the public health point of view nor economical.
For towns where one-storeyed buildings are common, and for supply to the ground level storage tanks in multi-storeyed buildings, the minimum residual pressure at the ferrule point should be 7 m for direct supply. Where two-storeyed buildings are common it may be 12 m, and where three-storeyed buildings are prevalent 17 m, or as stipulated by local bye-laws. The pressure required for fire fighting would have to be boosted by the fire engines.