Proper maintenance of elevated water tanks

Needs Address

The need to reduce impacts on drinking water, associated with temperature increases and precipitation pattern fluctuations due to climate.

Adaptation effects

• Prevention of deterioration of sanitation conditions and reduction of disease risk due to climate change 
• Securing water resources to deal with drought resulting from climate change

Overview and Features

Elevated water tanks provide water for a variety of uses, such as drinking, cooking, washing, bathing, toilet flushing, and commercial uses. Each use will be negatively affected if there is a an inadequate supply of clean water.

An excessive volume of water in an elevated water tank or vessel can result in loss of residual chlorine and permit the propagation of bacteria, while a translucent tank can promote algae growth.

Proper care and maintenance of elevated water tanks is best performed regularly by trained technicians.

(The Ordinance for Enforcement Article (item (ii), Article 55) of Japan's Waterworks Act (paragraph (1), Article 34-2), requires inspections of the following items for water supply equipment if the water vessel has a total effective capacity of greater than 10 m³.)

1. Inspection around water tank
   Area around tank must be clean and free of debris, contaminants, etc.
2. Manhole
   Confirm lock is in place.
   Confirm lid/cover firmly secured.
   Confirm nuts, bolts, packing in good condition, not deteriorating.
3. Vent pipe
   Confirm that shade is not damaged. Confirm insect screen is in place.
4. Overflow pipe
   Confirm pipe is directed downward. Confirm insect screen is in place at end of pipe.
   Confirm no shunting pipes.
   Confirm no damage to piping.
5. Tank interior
   Confirm no scale, no rust contamination.
   Confirm no suspended solids, no foreign substances present.
   Confirm no algae growing.
6. Upper portion, main portion of tank
   Confirm no depressions/dents, no water pooling on surface.
   Confirm no holes or damage.
   Confirm no oil pipes, detergents placed near upper portion of tank. 

Cost

Cost for inspection and cleaning: About 50,000 to 70,000 yen each time.

Note: This estimate is for tanks with a capacity of 11 to 15 m³. Actual costs depend on contractor. 

Energy source

none

Ease of maintenance

Maintenance must be implemented by trained technicians. 

Considerations

• Trained technicians are required. 
• Costs are incurred for inspection, cleaning, etc. 

Co-benefit, suitability for developing countries

• Stable supply of drinking water
• Improved hygiene and sanitary conditions
• Creation of employment for inspections, cleaning, etc.

Information Resources

Maintenance and Operational Manual for Water Storage Tanks and Waterworks (Ministry of Health, Labour and Welfare, Japan, March 2006)