Table 8.
Installation costs of concrete-based rainwater harvesting systems versus a cheaper wood-based alternative in native areas.
| Aspects | Quantity | Unit | Unitary price | Tank support | |
|---|---|---|---|---|---|
| Reinforced concrete support (S/) estimated in total prices | Local alternative (wooden board) estimated in total prices | ||||
| Cost of land | 1 | Global | 84.00 | 84.00 | |
| Cost of transport | 1 | Global | 1,200.00 | 600.00 | |
|
| |||||
| Cost of installation local labour | |||||
| 1 operator from outside the locality∗ | 10 | day | 110 | 1,100.00 | 0.00 |
| 1 officer from outside the locality∗ | 10 | day | 80 | 800.00 | 0.00 |
| 1 community labourer∗ | 10 | day | 40 | 400.00 | 0.00 |
| 1 carpenter from outside the community | 13 | day | 110 | 0.00 | 1,430.00 |
| 2 community labourers | 13 | day | 80 | 0.00 | 1,040.00 |
|
| |||||
| Cost of hardware materials (for concrete base vs. common wood alternative in native areas) | |||||
| 1/8-inch thick galvanised metal platen supports | 38 | Unit | 6.8 | 258.40 | 258.40 |
| Self-drilling fastening bolts for gutters, hexagonal head | 76 | Unit | 0.6 | 45.60 | 45.60 |
| PVC catchment funnel | 4 | Unit | 25 | 100.00 | 100.00 |
| PVC pipe, 4 inches | 4 | Unit | 20 | 80.00 | 80.00 |
| 4 inch × 90 degree PVC elbows | 16 | Unit | 6 | 96.00 | 96.00 |
| Codos de PVC 4 × 2 pulgadas, con ventilación | 4 | Unit | 6 | 24.00 | 24.00 |
| 2-inch PVC plug | 4 | Unit | 2 | 8.00 | 8.00 |
| Reduction from 4- to 3-inch PVC | 4 | Unit | 6 | 24.00 | 24.00 |
| 2 inch × 90 degree PVC elbows | 8 | Unit | 4 | 32.00 | 32.00 |
| PVC pipe, 2 inches | 8 | Unit | 13 | 104.00 | 104.00 |
| PVC tee, 2 inches | 4 | Unit | 5 | 20.00 | 20.00 |
| PVC ventilation cap, 2 inches | 4 | Unit | 5 | 20.00 | 20.00 |
| 3/4-inch PVC ball valve | 4 | Unit | 15 | 60.00 | 60.00 |
| PVC union with 3/4 inch thread | 4 | Unit | 3 | 12.00 | 12.00 |
| PVC reduction, 3/4 to 1/2 inch | 4 | Unit | 1.5 | 6.00 | 6.00 |
| PVC adapters, 3/4 inch | 16 | Unit | 1.5 | 24.00 | 24.00 |
| PVC pipe, 1/2 inch | 4 | Unit | 10 | 40.00 | 40.00 |
| 3/4-inch PVC pipe | 2 | Unit | 12 | 24.00 | 24.00 |
| Mixed PVC joint (thread and spigot), 1/2 inch | 4 | Unit | 2.5 | 10.00 | 10.00 |
| 1/2-inch PVC spigot union | 8 | Unit | 1.5 | 12.00 | 12.00 |
| 1/2 inch × 90 degree PVC elbows | 10 | Unit | 2 | 20.00 | 20.00 |
| 1/2-inch PVC tap | 4 | Unit | 15 | 60.00 | 60.00 |
| PVC glue × 1/8 gallon | 1 | Unit | 20 | 20.00 | 20.00 |
| Polyethylene tanks with ultraviolet protection, 1,100 L capacity | 4 | Unit | 475 | 1,900.00 | 1,900.00 |
| Black annealed wire, 16 gauge | 20 | kg | 5 | 100.00 | 0.00 |
| Black annealed wire, 8 gauge | 20 | kg | 5 | 100.00 | 0.00 |
| Portland cement type I | 32 | Bags | 26 | 832.00 | 0.00 |
| 3-inch wood nails | 15 | kg | 8 | 120.00 | 0.00 |
| 3/8-inch corrugated steel | 10 | Rod | 16 | 160.00 | 0.00 |
| 1/2-inch corrugated steel | 42 | Rod | 27.5 | 1,155.00 | 0.00 |
| 1/4-inch corrugated steel | 11 | Rod | 7 | 77.00 | 0.00 |
|
| |||||
| Cost of materials in the area | |||||
| River concrete | 4.5 | m3 | 120 | 540.00 | 0.00 |
| Ordinary timber for shuttering | 183 | p2 | 4 | 732.00 | 0.00 |
| Wood for tank supports | 461.5 | p2 | 4 | 0.00 | 1,846.00 |
| Total cost (4 systems) | 10,400.00 | 8,000.00 | |||
| Total cost (1 system) | 2,600.00 | 2,000.00 | |||
∗ Category of labour force, existing in civil construction (worker, journeyman, and labourer); p2 = square feet; and Bl = bag of cement weighs 42.5 kilograms.