Rivers are by far the filthiest source of water but people use them for irrigation all the time. During the dry season you may need water for the plants in your garden but if you redirect water from your kitchen [after you've used it] to your garden, this could save you a little money. Thoughts, please?
Greywater is a bit risky for a garden. While generally it should be fine, the cleaning products like dish soap that end up in this water can harm one's plants. If you have a sink that is used strictly for and washing (with mild soap) or drinking water, this can be safely reused. Laundry soap, dishwasher detergent and anything anti-bacterial can be lethal to plants if used in high enough concentrations. River water will often be dirtier to look at and it may be swarming with bacteria but the plants are designed to handle it. It is the chemicals we use in our homes that are a problem for our plants.
The best option would be re-directing water that is chemical-free to your garden. It may not be much but at least you won't be wasting water either. I've heard of people who get themselves an underground water barrel to collect such water for use much later when the need arises. In such a case I think even if you re-direct 4-5 liters a day after 3 or so months, you'll have enough to water a small garden for more than a week. Not so bad, if you ask me.
I've seen this done for large plots of land (fields) but not for gardens. I imagine that some harvests are better suited/genetically modified to handle the dirty water - something that's not happening with garden plants. And considering how so many chemicals are dumped these days in the rivers, I'd avoid using that water for growing food. It may help me save some cash, but water is cheap anyway so it's not worth risking any sort of chemical poisoning.
We have a massive drum in the garden that is full of rain water and we use that to water our garden, if that runs out (which it has done a couple of times in the three years we've been here) then I'll fill up the watering can from the tap in the kitchen. We don't live near enough to a river or stream to take water from it.
Its a great thought, but like Lostvalleyguy mention it can be risky for your garden. Do not use medicated water for plants.
Depends on the water really, soap residues and other chemicals mixed in the water might kill your garden. But as for me, yeah I do redirect my kitchen water to my garden and it isn't seem to cause any problems with the plants. I kind of taken the redirecting concept quite too far since I basically built a pipe system that would water the plants every time I drain the sink. I don't necessarily think it saves water, but it's better off spilled over the plants rather than go down to the sewers.
I have seen systems that use grey water from the house to recycle water used to help reduce the amount of water used and paid for. I use water that has been used to boil things like eggs or wash greens to water my plants. I am still concerned about chemicals used in cleaning the dishes and how they would effect my garden so I don't use laundry water or dish washing water in the garden.
