I conducted a quick keyword search using Google Keywords Tool and found two keywords with more than 1,000 global searches per month where the ‘Exact Match’ .com domain is available.
Plumbing is a very lucrative niche. There are many big cities and locations in the US that you can target through websites online. Many of them will have moderate competition.
When I started looking at the Internet with the intent of making money online, I thought creating a useful website can make you rich. I was wrong. Just creating a useful website is not enough for making money. You need to create a useful website in a profitable niche. Basically, you need to be in a niche where your visitors are willing to buy the products that you promote and are not afraid to click on ads.