First of all, go around your home and observe or write down where you are using water. List them by amount of water used, from the one that uses more to the one that uses less water.
You can go to internet and find out how much water you use in each activity, on average.

Here is a list of things that you can do at home to start saving water.  In general look at all the taps that are leaking at home. You may be wasting a huge amount of water. Have them repaired or repair them yourself. It is normally due to an old rubber seal that is easily and economically replaced. You can test if there are any leaks by controlling the water meter for an hour or two, when there is no water used at home. If the meters give a different reading, there is a leak at home.

In the bathroom:

• While washing your teeth, close the tap.
• Fill the basin to wash your face, instead of keeping the water running.
• Have shorter showers.
• Capture the water when the shower is running, waiting for the hot water to arrive to the showerhead. It is clean potable water. You can use this water to clean, flush the toilet, or water plants in the garden.
• Avoid having baths, use the shower instead. But if you have a bath, use the water after to water the garden or flush toilets. This water has some soap; maybe some dust and some of your skin cells, nothing more contaminant if you are in good health, so it can be safely used for other purposes. Use it to water trees and flowers, but not edible plants.
• Avoid using the toilet as a rubbish bin. Dispose of papers, tissues, cotton buds and other toiletries in the rubbish bin, instead of throwing it in the toilet.
• Flush the toilets with half flush mainly, if you have newer cisterns. A single flush toilet can use 12 L/flush (a bit more than a big water bucket). A dual-flush toilet can use only 3 L per flush, which is 75% less water.
• Check for leakages in your cistern. You can do that adding food colouring to the cistern, and checking after 1 hour if there is any colour appearing in the bowl.  
   
  

In the kitchen

• Use a plastic tub that fits in your sink to capture water that you use to clean your veggies, or wash the dishes. When using the dishwashing water, water only non edible plants (trees, shrubs, flowers, not your veggies).
• Separate the food waste from the water and put it in the bin, instead of using the shredder. You cannot reuse that water, unless you use it for the compost pile, and if you send it down the drain you are contaminating unnecessarily the water with organic matter that has to be separated later from the water, a costly process, in the wastewater plant.
• Use nature friendly washing liquid, it has fewer chemicals so it is better for your health, it contaminates less and you can use it safely when watering your garden (not veggies though).
• Don’t use your dishwashing machine until you have a full load. That may mean buying more cutlery, cups and plates, but it will pay back quickly, in water and electricity savings.
  
  

In your garden

• Water as much as you can with reused water from the household (grey water). Be careful with this water if you use strong detergents, soaps or bleaches, as they may affect the plants. Ecological detergents and soaps are gentler. Never use these waters on veggies beds, or on any edible plant.
• It is better to water twice a week deeply than every day lightly.
• Water the root zone.
• Water the garden when evapotranspiration is lowest, in the evening, at dawn or sunset.
• When buying new plants, chose those species that don’t need as much water as water loving plants. Native plants and plants from similar climates than yours will thrive in your garden and require less attention (water, fertilizers, care) than plants that grow in other climates.
  
  

Installing Water Saving Equipment
There are quite a few small ‘gadgets’ or simple technologies that can be used to save water at home.

In the bathroom and kitchen

• Water saving shower heads
• With the same principle, there are aerators with flow restrictors that you can purchase in DIY shops. They are specific for different taps, so you have to buy one that fits your taps.
• Rubber funnels. These are installed below the sink, in the drain, and redirect the sink water to the garden, or to a bucket that you can then use to water potted plants.
• Connect the washing machine to a hose that goes into the garden. Be careful in this case with detergents used, ecological detergents are better, normal detergents can burn plants. Also, don’t water the same area always with the washing machine outflow. Don’t use this water for vegetables or herbs gardens. You can also obtain the same washing results by using less detergent and slightly higher water temperatures (especially in colder countries).
  
  

In the garden

• Water saving hose nozzles are fitted with a hold-and-release mechanism whereby water stops flowing when you release the handle. Also, they are fitted with 3 or more spray size positions that allow you to control how much water is needed to water a certain group of plants.