When a home is treated for subterranean termites, the standard procedure is to inject termite chemical (termiticide) into the soil at intervals around the foundation wall. The chemical binds to the soil and creates a barrier that termites are not willing to cross. That soil barrier must not be compromised by digging to install utility lines, landscaping, renovation projects, or flooding. Disturbance of the soil can result in an area without chemical protection that can let termites reach the wood in your home.

If the area around your home’s foundation is flooded, it may or may not affect your termite protective barrier. Flooding from heavy rains can wash away treated soil from around the foundation but it depends on where, how much, and for how long. Most termiticides can tolerate short periods of wetness. You should contact the pest control company that did the initial treatment for an evaluation of the situation. Retreatment may be covered by a warranty or your homeowner’s insurance.

Termite Retreatment Has to Be Justified

By law, a pest control company cannot automatically retreat your home for termites, even at your request. According to EPA, retreatment for subterranean termites is only allowed if there is clear evidence of termite reinfestation or disruption of the barrier due to construction, excavation, or landscaping and/or evidence of the breakdown of the termiticide barrier in the soil.

Flooding Can Affect Termite Bait Stations, Too

If your home has been protected with termite inground bait stations, flooding can cause a problem here, as well, if silt and mud are dumped on top of the bait stations. In this case, the stations will need to be serviced, cleaned out, and the bait replaced. Some stations may have to be relocated to dryer ground (see Protect Your Home with Termite Bait Stations).

Be aware, too, that repair and replacement landscaping after storms can disturb the termite soil barrier even if it wasn’t damaged by the initial flooding. Any movement of foundation walls, patios, porches, or other structural elements as a result of the storm, or repairs after, might mean that a termite retreatment is necessary to restore a protective barrier.