Over the last few weeks, we've noticed that when we flush the toilet, it gurgles in our kitchen sink (the bathroom is on the second level and the kitchen is on the first level). When you drain the bathtub it gurgles as well, but not as much. Yesterday I put a load of laundry on to wash and when to water started to drain, the water started to gush out of the drain, making the basement floor wet, and it also makes the gurgling sound in our kitchen sink. My husband tried to open the trap under the sink in our bathroom, since we don't have any vents hooked up to our plumbing. I went to put another load onto wash this morning, but the water is still shooting out of the washing machine drain. Now when I run the dishwasher, water is coming out of the kitchen sink, but it drains rather quickly. Do we have a clog in our drain pipes or do we have to stack a vent outside?

Hi Mom,
"we don't have any vents hooked up to our plumbing." Well you just explained the gurgling. The system is venting through the water seal in the traps. That's one problem, no vents.
You have another in the drainage system itself. You ask, "Do we have a clog in our drain pipes or do we have to stack a vent outside?"
I would say both. By code,(and good plumbing practice) every fixture that has a trap must also be vented. Not having vents will slow down the discharge flow causing clogs, as you're finding out. Are you on a septic tank or city sewer? If on a septic tank it may need to be pumped. First snake and clear the drainage and then get a plumber out to advise you on how to vent the system. Good luck, Tom