Self-installation of a walk in bathtub is relatively easy but it will require basic plumbing skills. All you need apart from the tub itself is a drain and an incoming water supply.
After the bathtub has arrived, check it for any cracks or defects. As it will be holding water, any weaknesses could cause leaks. If you discover any, you should contact the provider for a replacement.
Next, you should remove the old bathtub by following these strict instructions: Firstly, turn off the water supplies and remove all of the relevant fixings securing it to your plumbing. There should be caulk sealant around the edges that will need to be broken. Once that is done, pull the tub away and dispose of as per your requirements.
Now check to see if any of the plumbing is damaged and in need of repair or replacement. If so, you will need to do this before continuing with installation. Once you are ready to install the new walk-in bathtub, lift and place it into the space where the old bathtub was situated. Ensure that the shoe fittings line up with the drain line that will be coming up from below. (It is also advisable at this point to have someone to help, as bathtubs can be exceptionally heavy.)
Now you need to ensure that the new bathtub isn’t uneven by using a levelling tool. If you find that it is, use the adjustable feet (which nearly all bathtubs have) to adjust the height and slant until it is completely level. After this, secure the bathtub to wall studs by using specified heavy duty nails. (You can ask at a local DIY store for these, and you might find installing them easier if you drill holes first)
Next, carefully secure the drain to the shoe fitting via the hole in the ceiling underneath it. At this point you are ready to install the water faucets that came with the new bathtub (or transfer from your old tub). This is relatively easy and can usually be achieved with a standard screwdriver. Then you are free to hook the water supplies back up and turn on, checking for any potential leaks at the lines.
Finally, use caulk to seal the edges of the bathtub. Let it set and then you are ready to use the tub!