On the outside of the house, ensure the faucet's mounting flange is flush against the siding. If the new faucet came with mounting screws and you have a suitable surface like wood or fiber cement siding, pre-drill pilot holes and secure the flange with the provided screws using a drill or screwdriver. This prevents the faucet from moving and stressing the pipe connection. To weatherproof the installation, apply a bead of exterior-grade silicone caulk around the top and sides of the mounting flange where it meets the house siding. Leave the bottom of the flange un-caulked; this creates a weep hole to allow any potential moisture that gets behind the flange to escape rather than being trapped in the wall.