Some Mountain View properties, especially toward the north end near Shoreline and the baylands, can stay wet longer in the rainy season. That's not true everywhere in the city, and we don't claim to know a specific lot before looking. What we do is observe where water pools, check how neighbors' yards slope, and dig a test hole to see if water shows up.
A French drain can help, but it needs somewhere to discharge. On a flat lot with a high water table, gravity may not give you a clean outlet, and then the conversation turns to surface grading, a sump with a pump, or a permeable surface that lets rain soak in. We'll explain those tradeoffs plainly, because the wrong fix is worse than a slower one.
Permits and rules also vary for drainage work, especially when water leaves your property or touches a public drain. Check with the city before tying into anything.