The water bill arrives and the consumption is higher than normal. In looking at the bill you realize it's winter time, your water consumption is down, but the bill says it is up as if its summer when your water consumption is higher. Then it hits you reliable a water leak! At some point almost all homeowners run into this problem.
Use the sandpaper to remove any loose particles from the hole. It is important for the surface to be properly prepared for these types of gutter water line repair.
After you have the stems out you should be able to find the washer on the "inside" end. If it is nicked, torn or brittle it is likely the cause of your drip. Even if it looks brand new, go ahead and replace it. You've already come this far. You can get replacement washers at almost any hardware store. Sometimes you may want to replace the whole stem, especially if the handle end is stripped out. It's best to just take the stem with you to the store and see if you can match it up. Most Do It Yourself stores have replacement stems for many popular brands. If your valve has a center diverter valve to switch the waterfrom the tub spout to the shower head the same process applies. Many times it is easier to replace the diverter stem than to repair it. This really depends on the design of the stem.
Clean the hole in the gutter railing first. It must be free of any debris, so you may want to clean the entire drain channel using a proper cleaner. In this way, you will have a clean surface area which will allow you to repair the hole more easily.
Be certain that the bathroom exhaust fan vents to the outdoors, not into the house or attic. If the exterior vent dampers don't operate properly or water line repair don't seat well have them fixed or replaced.
Keep your hands clean and dry. Plumbing jobs get slippery, so it's important to work with a pair of sturdy gloves so you don't lose your grip and accidentally hurt yourself or break something.
Plumbers can help keep small problems from becoming large problems. Do your homework before choosing a plumber and you can help to ensure that the job is done correctly and for a good competitive price.