Pool cleaning is a good directory niche for a plain reason: it is a recurring local service, bought by people who search for it by town. This is the Local Lab engine pointed at that market.
Every city with listings gets its own page, and every company gets a page built from one row of the import file. Owners can claim a listing, and the quote form sends a request to the firms that cover that city.
It shares its code with the locksmith and roofing directories. The three differ only in settings and data.