The Houston Amendments to the Uniform Plumbing Code Table 607.7 has specific guidelines for tank overflow and vent sizing, so in the event of a valve failure, the excess water will flow through the overflow to a floor drain. Especially on a fire tank system with large fill valves, this can be up to 1,000 gallons per minute of water pouring onto the floor of the pump room. Even when properly sized, floor drains may not handle this sudden demand (trash, etc.), and water can flood the pump room.

Many commercial buildings use storage tanks for Domestic (Potable) and Fire Water Applications, especially in Houston where it is required by Houston Amendments to the Uniform Plumbing Code Section 607. As water is used in the building, an automatic system is required to replenish the water and maintain a constant level in the tank. In domestic applications, this process can repeat multiple times an hour during peak demand loads. An automatic level-control system has two main components, Fill Valves and Controls.

Float Controlled Valves (Cla-Val model 124-01) are widely used on break tanks in commercial buildings. Float valves operate on the same principle as the valves in the back of a toilet: a float attached to a rod moves up and down with the level of the water in the tank. Float valves are simple and effective, but there are drawbacks in commercial applications. Most valves are installed on the top of tanks with the float rod directly attached to the valve, making them difficult to access and maintain. Tank-water-level adjustments are also difficult because the float rod length and float position must be changed on the valve itself.

When two float valves are used, there is no alternation between valves. The lead valve (shorter float rod) will always operate first, with the lag valve going long periods without use. This combination will eventually cause failures in both valves without proper preventative maintenance. Also, these systems typically provide little or no feedback to the Building Management System.