Why exposed exterior wood is the entry point in San Diego
Drywood termites do not tunnel up from anywhere. They fly, land, and chew in, which makes the condition of your exterior wood the deciding factor. The surfaces that matter are the ones people rarely look at closely: rafter tails and eave blocking, fascia boards behind the gutter, patio cover beams and posts, pergola members, wooden gates, garage door jambs, and window and door trim. Anywhere paint has failed, wood has checked, or a joint has opened is a candidate. San Diego's mild conditions work against you here. With summer highs around 76F and humidity near 69 percent, exterior wood stays in a moderate state that neither cracks apart nor stays soaked, which is a comfortable target. The practical program is unglamorous. Walk the exterior once a year, look up, and note where finish has failed. Sand, prime, and repaint those areas before summer, ahead of the daytime flights that UC IPM places in summer and fall. This is the rare pest problem where ordinary house painting is a legitimate control measure, and it costs a fraction of any treatment.
a termite calendar for San Diego
Several species fly here on different schedules, and the date and time you saw insects narrows things down quickly. Summer and fall daytime flights point to western drywood termites. UC IPM places drywood swarming during daytime hours in those seasons, and these are the flights that leave a scatter of wings on a sunny sill. Spring or fall afternoons following a soaking rain point to California Reticulitermes, the western subterranean group. Because San Diego averages only about 10 inches of rain, those windows are few and easy to anticipate. Late summer and fall can bring Pacific dampwood termites, whose presence indicates wood that has stayed wet rather than a soil colony. Western subterranean termites may also fly at other times, so an out of season flight is not disqualifying. Keep a note on your phone with the month, the hour, and where the insects were densest. Handing an inspector those three details, plus a few specimens, shortens the diagnostic conversation considerably and reduces the chance of buying the wrong treatment.
How California licenses the work you are buying
California's Structural Pest Control Board divides structural pest licensing into branches, and knowing that changes how you evaluate a company. Branch 1 covers fumigation. Branch 3 covers the control of wood destroying pests or organisms through the use of insecticides or structural repairs and corrections. A firm may hold one, both, or subcontract part of the work to another company. Ask which branch applies to what is being proposed for your San Diego home and who will physically perform it. If a fumigation is subcontracted, ask who carries responsibility for the outcome and who issues the completion documentation you will hand to a buyer later. This also explains why some companies can quote repairs alongside treatment while others cannot. Structural repairs and corrections related to wood destroying organisms sit inside a specific branch, so the ability to bid that work is a licensing question rather than a preference. UC IPM's note that drywood control products are not sold to the general public makes the point from the other direction: California treats this as regulated professional work throughout.
Shared walls, condos, and coordinated treatment
Attached housing is common across San Diego, and it turns a treatment decision into a group project. Drywood colonies live in framing that crosses unit lines, and a whole structure treatment covers the whole structure by definition. That means agreement among owners, a scheduling window everyone can meet, and often an association's involvement. The coordination usually takes longer than the treatment. For associations, exterior trim, roof framing, and common structure are typically association responsibility while unit interiors are the owner's, but governing documents vary and should be read rather than assumed. Renters should report pellets or tubes in writing with dated photographs. Structural pest work is the owner's responsibility, and if a fumigation is scheduled you will need to vacate and remove or bag food and medication. If neighbors are slow to agree, ask an inspector whether a localized treatment on your side is a reasonable interim step and, specifically, what it does not cover. That answer should be blunt, because a partial measure sold as a full solution is how people end up paying twice.
Buying the right amount of treatment
The most common expensive mistake in this market is buying a scope that does not match the finding, in either direction. Under buying looks like a localized treatment on one beam when pellets have also been seen in a bedroom and the attic was never inspected. The colony you did not find keeps working, and you pay again later. Over buying looks like a whole structure treatment for a single infested gate post that could have been replaced outright. The way to land in the middle is to make the inspection do its job. Ask how the attic was accessed, which areas were inaccessible, whether the patio cover and detached garage were examined, and what evidence supported the species call. Then ask each company the same closing questions: what exactly is covered by this price, what is excluded, how many reinspections are included, what a renewal costs, and which license branch applies. Write the answers down side by side. Two proposals that looked similar on price frequently stop looking similar once the scope columns are filled in.