Water decides many factors for the livestock industry. Without stock water on hand, the amount of rangeland that can be used is decided by how much water can be hauled in and stored properly. This leads to either livestock needing to travel long distances to get near the available water sources or an excessive grazing just near what’s available, especially when the only water source is based on well or utility water.
The amount of water needed for livestock, according to the Texas A&M AgriLife Extension office, is two gallons per 100 pounds of body weight, daily. This works out to typically 7 to 18 gallons per head of cattle, 8 to 18 gallons per horse and 1 to 4 gallons per sheep.
One alternative for sourcing the amount of water needed is rainwater harvesting, using the rooftop of any existing structure. Texas encourages rainwater systems as part of the State’s ongoing water plan and offers many incentives. Rainwater harvesting equipment and supplies are exempt for sales tax in Texas (Texas Tax Code §151.355).
The Texas Legislature allows the exemption of part or all of the assessed value of the property on which approved water conservation initiatives, such as rainwater harvesting, are made (Texas Tax Code §11.32)
There are also in many cases, local rebates and incentives for rainwater systems (Austin, Texas offers up to $5,000 in rebates).
On top of these rebates and tax-free incentives, collecting rainwater for later use decreases a rancher’s need for hauling in water or offers an alternative to their existing water supply.
The general rainwater harvesters rule of thumb is for every inch of rain that falls on a 2,000-square-foot roof, about 1,000 gallons of water can be collected. Texas typically has it’s rainy seasons followed by the dry, so the amount of storage is the deciding factor on how much rainwater harvesting can provide for your livestock.
Example of a ranch using rainwater:
Forty head of cattle in a 30-inch annual rainfall region with rare occasions of two months between significant rainfalls.
40 cattle x average 12 gallons of water per day = 480 gallons of water consumed per day.
480 gallons x 60 days of storage = 28,800 gallons of water storage needed as a minimum.
Capturing 28,800 gallons of water in a 1” rainfall requires a 48,000-square-foot roof (48,000 sq’ x .6 gal/1” rainfall = 28,800 gallons).