Riparian water rights come to the U.S. from English Common Law, and basically state that whoever owns the land on or near a stream or other course of water has the right to use that water as they need to. This doctrine was designed for use in areas where water is abundant, and often has less disputes than the other regulator of water rights, the prior appropriations doctrine. The latter is used mostly in the Western states, and was developed when and where water was scarce. Hence it’s basis as a ‘first come, first serve’ type of right.
Riparian water rights state that if you own the land, you can use the water. However, in the prior appropriations doctrine, it doesn’t matter if you own the land, because someone else could have found that water first, and have the rights to it. If that is the case, you would have to buy the rights to that water in order to be able to use it. It doesn’t matter if you are sold a property that includes access to a stream, because unless specific water rights are in the contract, any person could come along and dispute your right to use that water because they used it first.
Riparian water rights are friendlier, and allow every owner of land to use water as they wish from a stream that is near their home. It’s basically defined as the right to enjoy reasonable use of water that flows through your property. However, if you have 5 people on one stream using the same water source, you must be respectful and willing to share in the use of those rights, because everyone has the right to use it under riparian water rights rules. The older rule states that the natural flow must be left unchanged so that everyone downstream could use the water to their benefit.
Riparian water rights have changed, and now state that reasonable use is allowed by any riparian owner, as long as their use doesn’t cause problems or injury to the use of any other riparian owner that uses the same source. For example, if you divert a stream to irrigate your fields, you are harming the availability of the water to people downstream. However, if you divert a portion of that stream, allowing them continued access to the water, you are welcome to use it that way. Water rights can be hard to understand, but these are some important things to note about them before you get in over your head.