Before you install the new vanity in bathroom, you need to take off the old one for preparing the space. Make sure to switch off the water supply. It is recommended to switch off the water supply of the entire house, i.e. from the main point. Now, you need to take off the supply tubes of the cold and hot water from the bathroom vanity, along with the sink tap. Use of pliers is recommended.

Once you are finished with this, pick up a screwdriver or a socket wrench to remove the screws of your bathroom vanity. You can find them at the back corners, in braces or in a long line. Now, in order to make the bathroom vanity unit lighter, in order to take the entire unit off easily, you need to detach its counter top. Mostly, the counter top is attached with adhesive, and can be removed by a 14? pry bar. You can even use it to remove the backsplash out of the wall. However, you need to take care that you don't damage your bathroom's wall in the entire process. Inserting a wood shim at the back of the bar can help you in protecting the walls. Remove all the detachable drawers and other parts like doors from the vanity unit. Remove the sink beforehand by simply lifting it. Now, you can remove your old vanity unit by sliding it out. Check if the floor collides against the vanity's bottom. If it does then you will have to lift up its front part by the pry bar and insert some wood shims below it.

Well, removing the old vanity is just one half of the battle. For installing the new vanity unit, at first you need to identify the places where the new screws will be attached, and how all the pipelines including the drain lines are to be placed in it. Use a pencil and mark all of them. Make pilot holes at the marked places, to get a fair idea of the proper place of the drain lines and other pipe locations. With a hole saw of 0.5? larger than the overall dimensions of the pipes, drill along halfway from inside as well from outside to get a smooth finish inside your cabinet.

Use 2.5? screws to fix your new bathroom vanity unit in the wall. Once you have finished fixing the unit to the wall, install the sink. Fix up the taps on the sink and tighten them with the help of pliers. It is always recommended to wrap a rubber strip around its jaws as it protects your taps chrome finish. Attach the water supply lines to the taps, as before. Connect the tailpiece with the sink. Seal it with sufficient amount of silicone caulk. You can even use it to seal all around your vanity unit, to get a more secured fixture. But before that make sure that the new unit is exactly in the same place as the old one. Finally, attach all the water supply lines accordingly. Now, your new bathroom vanity unit is ready for use.