英语翻译An optional supplemental water supply,such as a well or

英语翻译
An optional supplemental water supply,such as a well or municipal
water,can serve as a security system for years of low rainfall
or if a system needs servicing and the cistern requires draining.
Because a water budget is based on average annual rainfall it will not be exact or guaranteed,but it should be used as a planning tool to help refine project goals as well as refine the water collection system and the intended water use.