You'll want a roll of paper towels or rags for drying and checking for moisture, a bucket for any active drips, and possibly a wrench or screwdriver for light tightening if you discover a loose connection. A small mirror can also be helpful for seeing hard-to-reach areas under sinks or behind toilets.

Even if the food coloring doesn't immediately appear, a slow leak might not be obvious. Check the flapper for wear or proper seating, and ensure the fill valve isn't overfilling the tank, which could cause water to continuously trickle down the overflow tube. Listen closely for any faint hissing sounds.

Yes, definitely. Faucets can also leak at their base where they meet the sink, or from the supply lines underneath the sink. Inspect carefully for water stains or dampness in the cabinet below, and check both hot and cold supply lines for any signs of corrosion or drips. Running both hot and cold water helps to identify leaks in different internal components.

Leaks in exposed pipes most commonly occur at joints and connections, so pay extra attention to these areas, especially under sinks and in basements. Be cautious when inspecting in damp basements or crawl spaces to avoid electrical hazards or mold, and always use your flashlight to ensure you have clear visibility and can spot corrosion or drips.