Everyone uses water everyday in their household tasks, at work, on the go or, pretty much anywhere. But there's some rules of thumb that not everyone has the chance to be privvy to; some save you money and some are simply common sense.
1. Cooking with hot water
One may think that it is a good idea to cook food with hot water straight off the tap to save time. And initially, this isn't a bad idea.
Hot water comes from your hot water heater. But in time, your hot water heater builds limestone deposits in the tank from the water coming in contact with the innards of your hot water heater. This means that when you cook that pan of hot water to prepare spaghetti, cook potatoes or anything else, all that limestone gets in your food, which is not good for your health.
So would changing your hot water heater be a good idea? Not really. All that limestone built up in the tank is also partly in your home's plumbing all over your house. The level of limestone might be lower for a while, but it will build back up as the new water heater ages.
Cold water on the other side does not pass by the water heater so it is free of those debris.
2. Wasting water
Everyday, we use water in a plethora of ways: clean dishes, laundry, cleaning, showering, bathing, brushing.... But sometimes we just let the faucet run. For example, who doesn't let the water run while you brush your teeths? Most people do. In the long run, this results in a large waste of water.
3. Water for non personal usage
During hot summer months, we sometimes use sprinklers to keep our lawns irrigated. But does it need to be clean water? If you live by a lake, you can simply use the lake water instead of the main water ways, which will cut down on drinkable water usage.
4. Laundry Machine
Like every piece of technology, laundry machines evolved over the years and now use a much reduced amount of water compared to machines twenty years ago. Some technologies such as HE Turbo or HE Turbo + help save water and use less detergeant which saves money and water. And most of the time, they also use less power.
A very good source of information is Water Use It Wisely website. They provide more than 100 tips on ways to save water and energy.