The gathering of water. I live not so very far away from a reservoir. When the reservoir was build it involved the loss of a valley, diverting a river multiple times and massive amounts of materials. However it is large and reliable. It's a place of beauty now but it came at a cost. The treatment of water for our consumption is also costly, especially when so much of it is flushed down a toilet or used for watering plants. This cost is obviously passed on to us, and I live in the most expensive area of the UK for water bills.
I had a conversation a couple of months ago with some friends to compare water bills. There is the same number of people in each home but their water bill is few times ours despite being with the same water company. The result of this conversation was the realisation that some of the practises that we follow make a difference.
We practise "if it's yellow let it mellow; if it's brown flush it down". You don't have to be religious about this for it to reduce your water consumption.
We also limit shower time. We don't shower every day. As housemate works on his own most of the time he showers even less than me. The timer below is an illustration of a piece of kit we were able to get free from our water company. At first I thought it wouldn't make much difference, but using it has reduced the time I spend in the shower. I never decided to use it to do that really, more it was curiosity about how much time I was spending in the shower. But observation causes change, and so I'm now naturally more conscious of the time spent in the shower.
We also practise that clothes aren't just automatically dumped into the wash. We consider if they're dirty or if they smell. I get changed when I get home for work into jeans, t-shirt and jumper usually. It was a habit I developed at school. I went to boarding school and we had to get changed out of our school clothes within half an hour of the end of school, so it's a habit I follow now. If I wear an item of clothing to make dinner and then sit on the sofa for a couple of hours it is not dirty. I hang it up before I go to bed and wear it again the next evening.
The last thing that we do is again shower related. We have a combi boiler so it takes a little while for hot water to come through when you want a shower so rather than waste the water I collect it in a bucket I keep next in the bathroom. This water is then used to flush the toilet from time to time.
They're small practises, simply things really but they evidently make a difference. The only equipment they involve are an egg timer and a bucket. They can be followed in a flat/apartment or a house or a farm. These aren't extreme steps either, or they don't need to be. We use less water than the water company expects two people to use, and I have further plans for ways to reduce our water consumption.