Walking across a path or your driveway with the water running is a definite water waster. Solve this by adding a shut-off device at the business end of the hose, or use a nozzle that allows you to turn the water off as needed.
Sprinklers lose water to evaporation -- so keep the air from gobbling up your precious moisture by using a soaker hose, which slowly drips water into the soil. Cover it with mulch and you waste next to nothing.
One of the most surprising things about a rain barrel is how quickly it fills, even in the lightest of rains. And the water you collect is free of city-water chemicals. Connect the rain barrel to your downspout or use a pretty rain chain to guide the water.
Note: Rain barrels are illegal in some areas. Check your local regulations before installing.
Weeds growing in your garden aren't just an eyesore; they also suck up valuable soil moisture from your plants. One of the best, chemical-free weed controls is a layer of mulch. It's air- and water-permeable and easy to plant into. Plus, organic mulches (such as shredded bark) decompose over time and improve your soil.
A faucet-mounted timer remembers to shut off your sprinkler so you don't have to.
Here's a hint: To prevent water runoff, set your timer to turn off your sprinkler, allow the water to seep in the soil, then start watering again.
Modify your hose with a quick-release connector to waste no water when changing attachments (and save you time so you won't have to run and turn off the water). One pull and you can switch to the best nozzle for the job.
If your sprinklers are on a timer, have you checked the water output? Place a rain gauge where it can collect water. Then adjust the timer to give your plants just what they need.
Here's a hint: Most plants need about an inch of water a week during the growing season.
Once established, drought-tolerant plants can handle extended periods without water. That's not to say they don't need water, just less than other garden plants. When you do water them, give them a deep drink and they'll be ready to handle the next round of drought.
Changing out weather-hardened O-rings is a simple fix for leaky hose ends. And don't lose precious water to a hole in the middle of the hose; fix the hole or invest in a new hose.
If your city mandates water rationing, ration across your landscape. Supplement your hose ration with water you've collected in rain barrels. Water your high-value plants first, followed by moderate-value plants.