Use the Google keyword tool and type in the name of your product or service. For example, if you are a plumber, type in "Plumber". Google will then list all of the words (aka keywords) that people type in to find a service like yours. You might see common variations like "Plumbing Expert", "Plumber Services" or "Pipe Plumber".
Do independent research using the Yellow pages, search engines and local business listings. Beforehand, make a list of what you are seeking in a plumber on Long Island. For example, years of experience, what services they provide, whether or not they have emergency service, areas of expertise, types of jobs they perform (residential, commercial, industrial) etc. Look for local plumbing service companies that are a match.
In order to summarise, the best plumbers to call out to repair your condition will be the plumbers who are able to get to you the quickest, provide you with a reasonable cost and have the expertise to carry out the job and complete it correctly. Everything else is actually not emergency service worth the work.
Not all faucets have or even need interior shut-off valves. If your valve is a "frost-free" style of valve then you wouldn't need a shut off inside. Frost free valves are a style of valve in which the Trustworthy plumber water shut off for the valve is located internally in the valve inside the house. The use of a frost-free valve is best suited for locations in which an internal shut off valve is inaccessible such as a location where the walls and ceilings are all finished. This style faucet can leak over time. If you have a frost-free valve that is leaking you will need to replace the washers internally on the valve to prevent the valve from freezing and bursting.
Sometimes repairs do not need to be immediate, but they should be quick. When you do not need emergency repairs, but cannot wait days for help, you should find a plumbing company offering same day services. This means you can call in the morning and have someone there to make the repair within hours. Since some companies do not offer emergency services, same day service may be the next best thing, so you should look for this offering if it is the best your Local plumber has.
Before choosing any plumbers in your area be sure you pick a contractor that has experience with similar projects as yours. Plumbing in your area isn't the same as say New York or Chicago, unless of course you are from one of these cities. Ask for a reference or two for plumbing jobs that they have completed in the past.
In short, the emergency plumber you hire should be from a reputable company. If you think that you can rely on him then you should look for another one. An emergency plumber should be skilled and should be able to deliver quality services to everyone.