Which of the following is a water-saving habit homeowners should adopt?

Choosing to run full laundry and dishwasher loads is a highly effective water-saving habit for homeowners. Both washing machines and dishwashers utilize a significant amount of water per cycle. By ensuring that these appliances are only run when they are full, homeowners maximize the efficiency of water use, thereby reducing the total amount of water consumed over time. This practice not only conserves water but also can lead to lower water bills, making it an economically beneficial choice as well.

The other options represent habits that do not promote water conservation. Keeping the faucet running while brushing teeth, for example, wastes a substantial amount of water that could be saved by simply turning it off. Frequent use of garbage disposals increases water usage further, as they require water to function effectively. Utilizing the toilet for trash disposal is another wasteful practice, as flushing away solid waste utilizes a significant amount of water for items that can be disposed of in a more environmentally responsible manner. Therefore, adopting the habit of running full loads in laundry and dishwashing machines stands out as the most beneficial practice for saving water at home.