Rainwater collection is also known as rainwater harvesting. Rainwater collection involves the collection and storage of rainwater run off. Typically a collection barrel or similar object is positioned to catch water as it runs from rooftops and other structures. Many people use untreated rainwater to irrigate flower beds, landscaping and gardens. Other uses include car washing and water for flushing toilets. Collecting rainwater is also beneficial to the environment as it reduces the amount of water that may become contaminated from oil and pesticides and then flow into a stream, river or pond. Calculating the potential for harvesting rainwater can help with planning and use.
Things You'll Need
- Pencil and paper
- Tape measure
Determine the amount of water that may be collected during a year. This will involve finding the cubic feet of water per year. Figure the square footage (A) of the collection area. This will be the area from which rainfall will be collected, such as a roof
Multiply the number (A) by the estimated or average inches of rainfall per year (B) for the location. The total will be referred to as (C). Refer to historical weather data and forecasts to figure the estimated rainfall per year.
Divide the multiplied number (C) by 12, which represents inches per foot, to determine the cubic feet of water per year which may be collected (D).
Convert the cubic feet of water collected per year (D) to gallons. Multiply the the total (D) by 7.43 to convert to gallons per year.
Tips & Warnings
- Keep in mind that the calculations do not take evaporation or other leakage into consideration.
- Photo Credit Hemera Technologies/AbleStock.com/Getty Images
How to Collect Rain From a Building Without Gutters
Rainwater catchment is catching on as a modern revival of age-old practical wisdom. With proper collection and storage of the water that...
How Do I Build an Underground Rainwater Storage Facility?
For every inch of rain that falls, a rainwater collection system operating at 100 percent efficiency can be expected to gather about...
How to Calculate Runoff Volume
Heavy rainfall can have potentially disastrous consequences for a homeowner, resulting in damage to the home and property. Determining how much excess...
How to Calculate Roof Rain Runoff
When planning your home and landscaping drainage needs, it is necessary to accurately calculate the amount of rain runoff from your roof....
How to Calculate a Catchment Area
Harvested rainwater can supplement or even replace municipal water for outdoor use. The amount of rainwater that can be captured depends on...
How to Calculate Drainage
Drainage is the amount of water absorbed by the ground in a given area. If you are planning to buy or use...