I would say no. If you have just a site and expect it to bring in customers, it will be a definite no.
Why? a website is a tool, it would be like leaving a cleaning wand in the middle of a room and expect the room to be clean when coming back.
What to do?
1. Content
Generate Content - Articles, Tips, Tools, etc... all these things for your site.
2. Link Building
You can start with getlisted.org - this site will help you promote your business on the locals. Don't FORGET REVIEWS! Try to get your customers to leave you reviews on google, yahoo, bing, etc... These not only help you, but will definitely make you stand out from the crowd.
3. Social Media
Build a following. Use these types to distribute news and updates about your company.
4. Time
Some of the more popular and reputable directories take time to get listed on, on top of that it just takes time for search engines to recognize you as a relevant source.
5. Learn some basic SEO strategies.
seomoz.org
When I first began my site first couple of weeks i'd get maybe 1-2 calls from online... after 6 months I now get about 10 clients a week. From doing these things of course I've had help from my web designer/seo consultant.