Galvanic Cathodic Protection Design for the Inside and Underside of a Pump Station Water Tank, Austin Area (2020, Reused in 2026)

A water district near Austin needed cathodic protection for a steel storage tank at one of its pump stations. In 2020 we prepared the design for a construction contractor: one system for the wetted inside of the tank and one for the underside of the floor.

Inside the tank

The interior system uses magnesium rod anodes, 2.024 inches across with a steel core, at 2.5 pounds per foot. Each hangs from the roof on a rope through its own anode handhole, so nothing is welded inside the tank and an anode can be lifted out and replaced from the roof. The anode lead is a stranded copper conductor with high molecular weight polyethylene insulation, soldered to the rod and sealed in epoxy inside a PVC sleeve, with a stainless eye bolt carrying the weight. Two permanent reference electrodes enter through their own handholes, and the wires run through a sealed conduit entrance to a test station. At the test station the anode circuit can be opened and the tank potential read against either electrode, current on or off.

Under the floor

The underside of a tank floor is out of reach once the tank is built. The external system adds sacrificial anodes on the soil side and runs a reference tube with electrodes under the floor, wired to a second test station, so a tester can read the floor potential from outside without lifting anything.

A second tank in 2026

In April 2026 the same interior design, with the same handhole, anode and reference electrode details, was issued for another water tank. The details carried over because the problem is the same: protect the wetted steel, keep the parts replaceable from the roof, and make the system easy to test.

Related services

Designs like this are described under cathodic protection design. Tanks are also covered on our page for integrity assessments of piping and tanks.