Rain water harvesting in Bangalore Mandatory | Deadline for Rain water harvesting is 31st December 2011

As per section 72A Obligation to provide rain water harvesting structure within 9 months from the date of commencement of the Bangalore water supply and sewage (Amendment) ACT. 2009, every owner or occupier of a building having a sital area of 2400 feet and above or every owner who proposes to construct a building on a sital area of 1200 sft and above shall provide for rain water harvesting structure in such manner with such condistions as many be provided in the regulations. Failing which the board may cause such rain water harvsting structure and recover the cost from the owner , as the case may be, as arrears of land revenue.

Introduction
Rainwater harvesting is an age old practice becoming popular due to the
realization of the potential of the rain water and due to the increased demand
for fresh water.
Rainwater is pure and soft. It has a nearly neutral pH and is free from disinfection, by-products, salts, minerals, and other natural and man-made
contaminants.
Though, the practice of Rooftop water harvesting is an age-old one,systematic collection and storage of water to meet the domestic water needs of the family is thought of recently. The cheaper and cost effective rain water harvesting components, readily available know-how on systematic and economic methods of construction will encourage the user to adopt this practice. There is also a need for creation of awareness and development of simple techniques to popularise roof water harvesting as a potential alternative source of fresh water.

The guideline is intended to serve as a tool for planning of residential and other rain water harvesting systems and also to encourage use of easily available precious fresh water through simple techniques.

Some of the benefits of rainwater harvesting are as shown below

1. The water is free except for the expenses for collection.
2. The harvested water is available where it is required as such there is no distribution cost.
3. Rainwater provides a fresh water source where groundwater quality is poor and can be used for recharging the aquifer.
4. The zero hardness of rainwater helps prevent scale on appliances, extending their use. Rainwater eliminates the need for a water softener.
5. Rainwater is sodium-free and good for persons on low-sodium diets.
6. Rainwater harvesting reduces flow to storm water drains, mitigates Urban flooding and also reduces non- point source pollution of surface and ground water.
7. Rainwater harvesting helps to manage the summer demand peak Through ground water banking.

Rain water storage (surface tank or under ground sump) & ground recharge (RCC precast ringwell) of minimum 20 ltrs. Per Sq. Mtr of roof area and a minimum of 10 ltrs. Per Sq. mtr. Paved open space. Provision shall be made. The open well/recharge well of depth of 3 mtrs(minimum) & diameter of .9 mtr.(minimum) without filling in the well (like aggregates jelly, sand etc.,) provision shall be made.

Chapter 2

Components of Rain Water Harvesting Rainwater harvesting is to capture, convey, and store the rainwater. It is useful for watering plants, domestic use, flushing toilet, car washing, ground water recharge, and reduces flooding of storm water drains.

Basic Components

• Catchment surface: the collection surface from which rainfall runs off

• Gutters and down pipes channel water from the roof to the tank

• Screens, first-flush system and filter components which remove debris and

dust from the captured rainwater before it goes to the tank

• Storage tanks

• Delivery system: gravity-fed or pumped to the end use