Salt can kill individual termites by dehydrating them, but it won’t eliminate a termite colony or protect your home from structural damage. The concentration of sodium chloride (table salt) needed to be lethal is high enough that you’d cause serious harm to your soil, plants, and potentially your foundation long before you’d make a dent in a colony that can number in the millions.
How Salt Kills Individual Termites
Salt kills insects through osmotic stress. When a termite comes into direct contact with a high concentration of salt, water is drawn out of its body cells faster than it can replace it. The termite essentially dehydrates. This works in a petri dish or when you sprinkle salt directly onto a handful of termites you’ve found in a piece of wood.
The problem is that this mechanism requires sustained, direct contact with a strong salt solution. Termites living inside wood galleries or traveling through underground mud tubes rarely encounter surface treatments in a meaningful way. You’d need to dissolve enough salt to create a solution concentrated enough to kill on contact, then somehow deliver it to every termite in the colony. That’s not realistic for an infestation of any size.
Table Salt vs. Borate Salts
When people read online that “salt” kills termites, some of that information is actually about borate salts, which are a completely different substance. Borates (compounds of the element boron) are the active ingredient in professional wood treatments and are genuinely effective at killing termites. Disodium octaborate tetrahydrate, the compound in products like Tim-bor and Bora-Care, is toxic to termites even at concentrations as low as 0.24% when impregnated into wood. A 15% borate solution applied to wood surfaces killed 100% of drywood termites within seven days in laboratory testing at UC Riverside.
Table salt (sodium chloride) does not share this effectiveness. Research on bamboo preservation found that crude lake salt, which is primarily sodium chloride, provided no meaningful protection against termites. All salt-treated bamboo samples were attacked and classified as “not durable.” Meanwhile, borax-boric acid treatments provided moderate resistance. The two substances are both technically salts in the chemical sense, but their effects on termites are not comparable.
Why Surface Treatments Can’t Reach the Colony
Even professional-grade liquid termiticides, products far more potent than salt water, struggle to eliminate subterranean termite colonies. A 2024 University of Florida study demonstrated why. When subterranean termites encounter a treated zone, the foragers closest to the treatment die quickly. Their bodies accumulate in what researchers called a “death zone” extending up to about 8 feet from the treated area. The smell of dead termites then causes the rest of the colony to reroute around it entirely.
The study found that as little as 1.5% of the colony population was actually killed by the treatment. The remaining millions of termites simply avoided the area and continued foraging elsewhere. Subterranean termites can travel several hundred feet underground, and colonies with millions of individuals can complete their life cycle and produce new colonies even after losing a small percentage of foragers. If commercial termiticides designed to be invisible to termites still only reach a tiny fraction of the colony, a salt solution has essentially no chance of doing better.
The Damage Salt Does to Your Property
Applying large amounts of salt around your foundation creates a different set of problems. Excess sodium in soil disrupts its physical structure at a fundamental level. Sodium ions break apart the bonds holding clay particles together, causing the soil to swell, disperse, and then harden into a crust when it dries. This plugs soil pores, reduces water infiltration, and destroys aeration. Over repeated wet-dry cycles, the damage compounds.
For plants, high soil salinity pulls water away from roots through the same osmotic mechanism that dehydrates termites. Grass, shrubs, and trees near the treated area will show signs of water stress even when the soil is moist, because their roots can’t absorb water against the salt gradient. Saline soils develop a visible white crust on the surface, and the reduced permeability can cause water to pool against your foundation rather than draining away, potentially creating the exact moisture conditions that attract termites in the first place.
Concrete and metal are also vulnerable. Salt solutions that seep against foundation walls accelerate the corrosion of rebar inside concrete and can degrade the concrete itself over years of exposure. You’d be trading a termite problem for a foundation problem.
What Actually Works
For drywood termites (the kind that live entirely inside wood), localized borate treatments are effective when applied correctly. Professional-grade borate solutions penetrate wood and remain toxic to termites for months. In lab tests, borate dust achieved 100% mortality within a week, and liquid solutions maintained significant killing power even 60 days after application.
For subterranean termites, which cause the most structural damage in the U.S., the standard approaches are bait systems and soil-applied termiticides. Bait systems work by letting foragers carry slow-acting toxicants back to the colony, gradually poisoning the queen and reproductive members. This addresses the core limitation of any surface treatment: reaching the colony center rather than just picking off a handful of workers at the perimeter.
If you’ve found termites in your home, the scale of a colony and the difficulty of reaching it underground make this a situation where professional treatment pays for itself. Sprinkling table salt on a few visible termites might kill those specific insects, but the colony behind your walls or under your slab won’t notice they’re gone.