The height at which a fold-down shower seat should be mounted depends on various factors, including the user's height, mobility, and personal preferences. However, there are some general guidelines to consider when installing a fold-down shower seat:

• ADA Guidelines: If the shower seat is being installed to comply with accessibility standards, the Americans with Disabilities Act (ADA) recommends mounting the top of the seat surface at a height between 17 and 19 inches (43-48 cm) above the shower floor. This height range is intended to accommodate a wide range of users with different mobility needs.
• User Comfort: For non-ADA installations, you can adjust the height based on the user's comfort and needs. Some people may prefer a slightly higher or lower seat depending on their height and ability to transfer in and out of the shower.
• Consider the Shower Space: Ensure that the shower seat height does not interfere with the showerhead or other fixtures. The seat should be positioned in a way that allows the user to sit comfortably while also having access to the water for showering.
• Professional Advice: If you are uncertain about the height or have specific requirements, it is best to consult with a professional contractor or an occupational therapist who specializes in accessibility and mobility solutions. They can assess the user's needs and recommend the most appropriate height for the fold-down shower seat.

Remember that the main goal is to provide a safe and comfortable showering experience for the user, so the height should be chosen accordingly.