It will depend on your abilities, the age of the drain, and the manner it is plumbed and ultimately where it is plumbed to (main sewer line or French drain??? ). I personally would start with the easiest things first, such as a visual inspection of the drain line from under the house (if on raised foundation ) or renting an auger and rootering out the drain yourself. If you can clear it, you saved yourself the expense of a plumber to do it for you. If you can't clear it, a plumber is only a phone call away.