Many of the laws discussed in these pages apply only to diversions from streams. Many landowners mistakenly think their diversions are exempt from these laws because they rely on wells or springs that appear unconnected to any stream. In many cases this is a mistake, because California law takes a very broad view of what constitutes a stream. Following is a discussion of the law as it applies to wells and springs.
Wells
Although a well by definition pumps groundwater, it may still be considered a diversion from a stream. This is because California law recognizes the existence of subterranean streams, which are defined as groundwater that is “flowing through known and definite channels.” If your well draws water from a subterranean stream, it is treated just like a diversion from a surface stream under the laws discussed here – including water rights law and Fish and Game Code Section 1602.
Unfortunately, it is very difficult in practice to conclusively determine whether a well draws from a subterranean stream as defined by law. As a general rule, it is safe to say that the closer a well is to a surface stream, and the more direct its observed influence on surface flow (and vice versa), the more likely the agencies are to treat it as a stream diversion. Some guidelines:
• If a well is directly adjacent to a surface stream, such that it takes “underflow” from the stream, it will be considered a stream diversion.
• If a well taps into a deeper aquifer that is hydrologically separated from the stream aquifer by an overlying impermeable layer, it is not a stream diversion. This situation is very rare in mountainous regions of coastal California.
• If a well does not tap into a deep aquifer with an overlying impermeable layer, whether it is treated as a surface diversion will likely depend on its proximity and connection to a surface stream.
When in doubt, the safest route is to assume a well is a stream diversion unless you have concrete evidence to the contrary. Assuming your well is a stream diversion, it is governed by riparian water rights. You should file a Statement of Water Diversion and Use for the well. If you store water, you will need to obtain an appropriative water right, most likely through a Small Domestic Use Registration. Finally, you should consider notifying CDFW to see if you need an LSA Agreement.
Springs
The basic legal rule is that if a spring flows does not flow off your property under natural conditions (that is, when no water is diverted from it), then you may use it without any regulation from the state. If the spring does flow off the property, then it is considered a surface stream, and a diversion from it is subject to the same rules as any other stream diversion, including water rights law and Fish and Game Code Section 1602.
In practice, you should be very careful when concluding that a stream does not flow off your property under natural conditions. In particular, CDFW takes a very broad view of spring jurisdiction in coastal California – largely because springs are the most important source of streamflow during the driest months of the year.