A home warranty can cover a slab leak, but only if your contract says so. Many contracts exclude slab leaks or cap what they pay, and many also leave out the cost of breaking through the foundation and the water damage the leak caused. Some companies sell slab leak coverage as an add-on.
A home warranty is not insurance. In Texas it is a residential service contract, licensed by the Texas Department of Licensing and Regulation, not the insurance department. TDLR describes these contracts as paying to repair or replace home systems, plumbing included, that fail from normal wear or a defect, and not for the perils an insurance policy covers. Under a slab, the warranty is aimed at the failed pipe, while homeowners insurance is the policy that may answer for sudden water damage.
Before anyone touches the floor, read the plumbing section of the contract. Look for the words slab, foundation, concrete and access, the dollar limit per claim or per term, whether a pre-existing leak voids coverage, and whether a reroute instead of a spot repair counts as an approved fix. Then call the warranty company before hiring a plumber. Many contracts let the company choose and send its own contractor, and a repair you arrange yourself may not be reimbursed. Ask whether locating the leak is covered too.
One honest limit: contracts vary widely between companies, and even between plan levels from the same company, so no general answer replaces the wording of yours. Get any approval or denial in writing. If a claim stalls or is denied, TDLR runs an ombudsman that steps in between homeowners and residential service companies.