(RNN) - The key to your front or back door could be the key to danger. Would you ever knowingly put a lock on your house that a complete stranger can open? You may not know it, but you may have already done that.
"It just doesn't make sense when you buy a lock and someone else has a key to it, period," said locksmith Glen Peifer. "I would like to know that my key is the only one that fits the lock."
It is a danger most consumers do not consider.
When you buy a mass produced lock, the chances are very good that someone else has the key to your home.
"My mom always said you get what you pay for," said Ginger Watson, who was pleased with the price of a dead bolt lock she purchased at a big box retailer.
She was not so pleased when we told her a little known secret: Lock expert Glen Peifer says most big box retailers only carry a limited number of different keys for each brand of locks they sell.
"I would say it would be very low. It would probably be under 10 or 20," said Peifer about the number of keys.
Take Schlage for example. The company manufactures 30,000 different keys.
A spokesperson for Schlage says they constantly rotate the thousands of key codes they ship to retailers.
But how often are retailers rotating their inventory?
At one Home Depot, we found seven Schlage deadbolts on the shelf. All seven had the same key.
Out of nine handle and deadbolt sets, there were only two different keys available, meaning every other customer would have matching locks on their doors.
Our investigators quickly found matching keys for several brands, including Defiant, Gate House, and Kwikset.
Finding a match to Ginger Watson's Gate House-brand lock was as simple as matching a serial number on her key. It only took about 10 seconds.
"Scary. Because someone could be helping me in the store, look at the number, 'Here you go ma'am'. Memorize it. Grab the same thing right quick or wait and just trail me home," said a shocked Watson.
Key manufacturers tout the convenience of matching keys to customers who want the lock on the front door to match the back door.
But safety experts say that convenience comes with a risk, in situations you may not have ever thought about!
Maybe a criminal would not go so far as to buy up a bunch of locks and try to find a key that matches yours. But think about how often you surrender your keys, i.e. the valet, the car wash.
And what about those membership cards on your key ring that need to be scanned? Have you ever just tossed your entire set of keys into a drive through window?
Safety experts say you should always separate your car key from your house key, lowering the chance of someone stealing your key's identity.
"Maybe they think what are the odds?" said Peifer. "But I think if they really knew what the odds were they would choose not to do that."
When our investigators asked Home Depot and Lowe's how many different keys are available in their inventory of locks.
Home Depot said, "We don't break out the information you are requesting."
Lowe's said "We aren't able to provide information on inventory."
Schlage offers this advice: Ask the retailer where you purchased your lock if they will re-key it for you.
The safest solution, albeit the more expensive solution, is to invest in a lock that requires a custom key that cannot be duplicated.
"Do they not understand that the next customer that comes by and grabs this lock off of the shelf, that they have a key to their house?" said Peifer.
A possible key to danger, when consumers unknowingly risk security for convenience and lower prices.
Click here to read a statement from Home Depot:
Click here for security tips provided by two key manufacturers: