That's why I suggest everyone should get an inspection.
What there looking for is the mud tunnels they make to get into the house along the foundation, around any pipes that go through the foundation and any damage to the bottom plates. All they need is one tiny crack and they can get in. Sometimes they have found a tiny hole where there's missing morter and can go through the voids in a concrete block up into the bottom plate then up into the wall studs and never be seen Until at some point they come through the base board or in the spring they produce what's called swarmers. The queen starts producing flying termites, I've seen them so bad the lady was using a shovel and a big floor broom to sweep them up. There being produced so they can fly off and start a new colony. They not real strong flyers and count on the wind to help them. Once they land they can morphis to become a male or a female in case two males happen to land in the same area.
Here's something on the only termites I know of that you would need to tent the whole house.
And there's only one know case where they have been found in CA.
And here's another great source on what to look for and what they look like.
And yes there are companys that have heat seeking sencers that can check the walls and there are even termite sniffing dogs, no joke, but good luck finding one.
Lots of people have called me telling me I think I have termites because I can see them, unless there swarming it's more likly all you will see until it's to late is the mud tunnels.
One house I went to they had eatten through a wood floor and ate holes in a phone book laying on the floor.
One I went to every year had them near the back porch because they insisted on stacking there fire wood up againt the side of the house. One guy had a slab floor garage and had leaned a piece of plywood on the outside for some reason and they had climped up through the plywood and went into the T-111 siding.
Never ever store wood or leave wood under or near a foundation. Any time I see mulch piled up againt a foundation, a dripping outside faucet, land scape timbers touching a foundation, ( read the tag right on the lumber, it's not below ground rated, once you back fill with mulch or top soil it's below ground and it's going to rot, use 4 X 4's 4X 6's or 6 X 6's instead, there below ground rated) leaking gutters, there's a good chance I'll find termites in that area because they need moisture to live.
They now make mulch with a termicide in it for that reason.
PS unless your well is close to the house do not let anyone tell you that you need bait stations, Terminex calls them the Senacon system. There going to charge you about $100.00 each for these. You can buy the exact same thing in any Box store for about $25.00 for 20 of them. ALl they are is a plastic tube with a stick of pine with a nail in it at the top. Then there going to charge you a fee every year to come check them. All they do is remove the cap, pull out the stick and see if there's termites, if there is they replace the stick with a poison bait that gets taken back to the nest to kill the queen. The problum is they place them 10' apart and about 4' from the foundation, termites are blind and not likly there going to be messing with the bait staions when there's a full course meal waiting for them in a whole house.