Four year olds are just past the toddler stage, and many things are definitely done by then. They are potty trained and in the limbo age between baby and school aged. Though their maturity and ability to understand is much more than when they were two, without firm parenting, their stubbornness may be at the same level. Whether you have been implementing parenting strategies from the beginning, or you are just now beginning to learn how to give your child a disciplined environment (which is not necessarily the same as strict), creating good discipline boundaries will make your child more comfortable and will help with much of their behavior as well.
Kids are not misbehaving if they don't know what the rules are. Though it's possible that an adult will understand the implications of bringing a pail of water into the living room to play submarine legos, a four year old will not. They don't yet have the capacity to fully understand cause and effect scenarios, though their brains are on their way to forming those connections. Instead, make rules that are general and simple, and don't make exceptions for them. In this case, if they want to play with something new in the living room, then ask a parent first. The key is to make the rule open to saying yes or no, but not to deviate from it. The more chinks in the rule, the more they will look for more, and the less effective your limits will become.
Kids won't get it once. Repeat rules often, not just in situations where your child is in trouble. One great way to do this is to praise them for following the rules. (If you're busy, this is especially important because they will try and gain your limited attention for being good. Without this step the only way they have to get your attention is to be bad.) If you tell them what a great job they are doing playing only in the living room with the toys that they asked Mom about, this is a great way to reinforce the rule without being mean.
Divert and Redirect
If your child is getting into a lot of trouble, they may need redirection. Take them on a walk where they can look around at the world and see what other things are out there. Bring out a game or toy that is special, and allow them a chance to examine it. Make up a new game. Do something that will create a chance for your child's energy to be used in a more positive way. This can help your little one to get the energy urges out without destroying your home or relationship in the process.