2. Clean the drain. A dirty drain can also cause water to settle in the top corner of a bathtub. Clean the drain by pouring a cup of baking soda and a cup of vinegar down the drain. Let it sit for 15 minutes, then flush the drain with hot water.
3. Check the slope of the bathtub. The bathtub should be sloped so that water drains properly. If the bathtub is not sloped properly, water can settle in the top corner. You can check the slope of the bathtub by using a level. If the bathtub is not level, you can shim it up to ensure that it is sloped properly.
4. Install a shower curtain. A shower curtain can help to prevent water from splashing into the top corner of the bathtub. Make sure the shower curtain is long enough so that it covers the entire bathtub.
5. Use a bath mat. A bath mat can help to absorb water that splashes out of the bathtub. Place the bath mat in front of the bathtub to help keep the floor dry.
6. Install a shower diverter. A shower diverter can help to direct water away from the top corner of the bathtub. Install the shower diverter to the shower head to help keep water from settling in the top corner of the bathtub.