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What the test is
The drain system is temporarily plugged at the main cleanout and filled with water to slab level. If the water level holds, the lines under the slab are tight. If it drops, water is leaving the system somewhere beneath the house, and further isolation testing narrows down where. It is a diagnostic, not a repair: the result is information about what is happening under the slab.
When an inspection recommends one
Plumbing is its own licensed trade, and testing is performed accordingly. Our role is the structural read: whether the moisture pattern under your foundation points at plumbing, and what the elevation data says the leak is doing to the slab. When the test comes back clean, that possibility is eliminated honestly and the evaluation moves on.
Cardinal performs this work across the Dallas-Fort Worth Metroplex and the Houston area.
Frequently asked questions
No. It is recommended when the movement or moisture pattern points at under-slab plumbing. Most inspections do not need one, and we say so when yours does not.
No. It uses the existing cleanout, fills the lines with water, and observes the level. No slab is cut for the test itself.
The leak gets located by isolation testing and repaired by a licensed plumber. If the leak has already caused movement, the elevation data tells us whether the foundation also needs attention, and in what order the work should happen.
Start with an engineer
Tell us about your property and we'll schedule a free, no-obligation inspection. Your request routes to the right team: commercial, residential, or new construction.