What is the maximum allowable water depth for spas according to standards for permanently installed residential spas?

The maximum allowable water depth for permanently installed residential spas is 4 feet. This standard is established to ensure safety for users, particularly since many spas are designed for relaxation and therapeutic use rather than for swimming activities. A depth of 4 feet provides enough immersion while reducing the risk of accidents or drowning. Additionally, it helps in maintaining effective water circulation and sanitation, which are crucial in spa maintenance.

Deeper depths can pose safety challenges, especially for spas that may cater to a variety of users, including children and inexperienced swimmers. Ensuring that the depth remains at or below 4 feet makes it easier for users to enter and exit safely and reduces the likelihood of risky situations arising from deeper water.