Unless your home is built of steel, it will get termites every ten years, and here is why. Where subterranean termites tunnel up from the ground, western drywood termites spread their numbers by taking to the air in swarms. These swarms can land on any house and they will find an entrance into an attic which becomes their new home. They are extremely prevalent in Southern California. The net result is that if a home has not been treated in the previous ten years, you should EXPECT that it has termites. Often buyers of new homes are surprised to find out that the home has termites; usually this is because the termites infected the lumber at the lumberyard and the home had termites from the very first day. The important thing to remember is that it can take decades for a colony to build up to the size of an eastern subterranean colony that can do a lot of damage. Most often, if caught within a few years, the damage will be slight. So, if a home has termites, don't be surprised, and don't be overly concerned - there are good treatment options for drywood termites.

Treatment Options
Whole-house tenting with Vikane® - Sulfuryl fluoride (commonly marketed by Dow Chemical under the name Vikane®) is the most comprehensive way to make sure that a home is free of all termites. Vikane® is an inorganic gas with an extremely low boiling point, and is a gas at room temperature. The house is covered with an impermeable tent and the gas is released inside the home. It disperses, and because it is so toxic that it kills every living thing inside the home and attic. Houseplants have to be removed or they will get killed also. After a day, the tent is removed, the windows are opened, and the gas is exhausted to the outside air.

After the treatment, there are no termites, spiders, roaches, mice, or rats inside the home. Because of its low boiling point, there is no residue, and, according to Dow (the manufacturer), dishes do not even need to be rewashed. This is VERY effective at eliminating all pests. Unless you have a philosophical objection to the use of chemicals, this is the preferred treatment because it is so effective at thoroughly eliminating all the termites.

Issues - No matter what any of the pest control companies may say, Vikane® is DANGEROUS stuff to breathe, and you should stay away from the house until the home is completely aired out; if you breathe it, it can kill you, so you need to use care. (We know of anecdotal stories where a real estate agent went into a house that had just been treated and breathed in slight amounts of residual pesticide and died within a few days.) Although the manufacturer doesn't say that it is necessary, you might even have fans to air out the house for a second day before you move in just to avoid breathing an trace amounts of the toxin. Also, you DON'T want to tent a house if you KNOW you are infested with rodents; doing so will kill them in the walls and you will have a huge expense removing them. If you have rodents, trap the rodents first, and then tent the house. (Note: Theoretically, the chemical dosage is set for just killing termites; in practice, rodents, fish, lizards, and every living thing gets killed.) Finally, we like to notify nearby neighbors know when the tenting is going to occur so that they can keep pets/children inside just in case fumes waft towards their home with the breeze.

Microwave
This is a new treatment approach and has a some major benefits. Microwaves are directed at the infected area and simply cook the termites and any other insects in their path. No chemical exposure or residues occur. The primary disadvantage with the use of microwaves as a treatment is that its use assumes that the pest control company knows where the termites are residing. Often evidence of termites can simply be inaccessible (e.g., in a wall), and thus the pest control company does not know where to apply the treatments. Alternatively, an establishing colony may be small and the evidence may be slight and overlooked. Thus, the major advantage of whole house tenting is that it will likely kill all seen and unseen colonies in the house. Finally, studies at UC Berkeley evaluating the effectiveness of various treatments shows that even when the location is known, microwaves can result in less than 100% kill rate. (See: http://www.cnr.berkeley.edu/lewis/eval6.html.)

Heat
Another approach to spot treatments is the application of heat to kill the insects. Simply put, termites will die with a sustained exposure to temperatures of 120°. In addition to having the same problems of identifying all the locations of the termites associated with microwave treatment, there is the additional problem of heating large timbers long enough to get the core of the timber up to the required temperature. Thus, heat treatment is probably a less-desired choice than the newer microwave treatment.

Electrocution and other treatement options
Electrocution is another treatment approach, though it has a number of limitations, including a less-than-100% kill rate (See UC Berkeley study). There are also other chemical treatments for localized treatment. Because of relatively rare use of these other treatments, they are not covered in this article.

Cost
The primary reason why many homeowners opt for localized treatments with microwaves or heat is to minimize the cost. Tenting a house with Vikane can cost anywhere from $3,000 to $5,000, and this cost is usually borne by the seller who is typically required to provide an all-clear termite clearance. Since the seller's obligation is to get an all-clear, many sellers seek to pursue the cheapest option available in getting it. If microwave treatments only cost $1,000, and the pest control company will provide the all clear, then why not use the microwave treatments?

Negotiation
First, sellers should get a termite inspection done BEFORE putting the agree to an offer so that they have a rock solid idea if their home has termites and what it will cost to remedy them. To the extent that buyers WANT whole-house tenting in the event that termites are discovered, then that can be written into the contract when the offer is made. This is probably a GOOD IDEA with an older home that has not been treated in 15 or more years.

Final Notes
Of course, we are not pest control specialists and have not been trained in the application of termiticides and chemicals. If chemical treatments cause concern, then you should contact the Pest Control Board or a licensed pest control operator or the California EPA. Please note that some colonies of the rare (in California) Formosan subterranean termite have been identified in San Diego county, and this termite has different attributes than the western drywood termite and is known for causing rapid damage to wood.

Additional Reading
We will be glad to help you through the entire purchasing process, and we will be glad to provide you additional information. If you want to read more about termites and treatment options, you might want to visit the termite page at UC Davis (http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7440.html).