Collect rainwater from the gutters in your house inside a tank. Then use a pump to circulate water for gardening/toilet/cleaning.

Simple schematic attached:

Yup in my housing area they provided a tank outside the house with a pump. I just gave the pump to my dad to build pressure in his house, threw away the RWH tank and joined the pipe work to my main tank in ceiling. So now my garden using tank water.

Gardening, washing car/proch, in some cases toilet flush also can use