Like when ppl say don’t wash your yard or car with a hose. Isn’t the extra water or for that matter all water either seeping underground and adding to groundwater table or being evaporated into nature to be recycled? In both cases the water will be filtered enough to be potable….
In: Physics
If your supply of water can only supply, say, 100 cubic acres of water per year then you have to keep your consumption below that or you will be in ‘deficit’.
Fresh water comes from many place. Ground water, mountain snowmelt, desalination etc. Once it’s ‘used’, then it’s generally treated and released back into a river or the ocean, assuming it goes down the drain. If you use that water for agriculture, or watering your lawn then most of ultimately evaporates into the air, (not trickling down into the deep aquifers that we pull safe water from.) This also causes problems for downstream users for which there are often agreements in place that they need so much supply per year as well so they can drink and have golf courses. If there’s a hydro dam along the river, then it literally needs a certain amount of flow or it will not work and you’ll have a power deficit. …So you also can’t pull too much for political reasons. (Even the local wildlife needs water but that’s a whole different issue.)
Especially when it comes to snowpack and ground aquifers, there’s only a limited amount. If you use too much snowmelt, then the river runs dry because you’re pulling it out of a river. Aquifers can only recharge so fast and if you pull to much then the ground begins to collapse and you permanently lose storage capacity. There’s also a limit to how fast you can pull from an aquifer since the water is literally mixed with sand and can only flow so fast. Pull too much and your well goes temporarily dry. Worse, if a network of wells all pull to much, you can cause all the wells in a whole town or city to go temporarily dry.
Even desalination has limits because the waste water from the process, brine, is incredibly salty and toxic to life. Therefore, releasing too much of it in one location will create massive dead spots in the ocean. That, and the incredible amount of electricity it needs to make the whole process possible, makes desalination a ‘last ditch’ effort.
In all cases, it’s possible to ‘expand’ supply, by building giant reservoirs or capturing and intensively treating the sewage outflows or building huge pipelines to access far away supply, or simply drilling more wells… But all this cost money and takes time. The more infrastructure you build, the more your taxes go up. The more technological your interventions, the more your taxes REALLY go up. It’s also not possible to build overnight, so expanding supply doesn’t help you tomorrow, it helps next decade.
In the end, the cheapest and often easiest thing is to simply not waste the water you already have.
Let’s say it rains once per week. By that your rain barrel gets filled. In a simpler setting you would use that water for all water uses like drinking, cooking, washing and watering your fields. We neglect other sources in this example. If you waste water for less important stuff like washing your car or watering a golf course you might run out of water to drink until the rain comes next week
The water you drink or use for cleaning is not gone, but it’s dirty and therefore unavailable. We can clean it but that requires energy. If we just rinse off our car (without detergent) the water used us not really dirty and could be reused to water plants. But with most uses it flows downhill. In most cases we would need energy to pump water uphill again. If we don’t have the energy or money to clean or pump the water we have to wait for rain again
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