Troubled Waters: Surface Water Law and the Montecito Floods

By Steven A. Blum   |   February 8, 2018

In last week’s issue of The Montecito Journal, I explained that if the facts show a fire, covered by a typical homeowners’ insurance policy, was the “efficient proximate cause” of a later mudslide, then mudslide damage could be covered under a homeowners’ insurance policy.

On January 29, California insurance commissioner Dave Jones adopted the same analysis in a press release that called on all insurers to cover homeowners’ losses from the recent mudslides in our community.

Commissioner Jones stated that “preliminary indications are that the Thomas Fire burned vegetation which would otherwise have absorbed rainfall and held soils in place, which in turn resulted in the mudflows, mudslides, debris flows, or landslides” that ravaged Montecito. “If the evidence shows the Thomas Fire or another peril covered by a homeowner’s insurance policy was the efficient proximate cause of mudflow damage, I expect insurance companies to step up and cover these financial losses.” Commissioner Jones’s pronouncement underscores that affected homeowners should promptly make insurance claims.

I also explained in last week’s article why collective litigation (class action, mass tort) is not designed for mudslide cases, because each property is uniquely situated in relation to the web of hills, creeks, culverts, and roads in Montecito. Impacted homeowners may very well have claims against upstream/upslope or downstream/downslope neighbors, implicating their liability insurance, and this will likely result in conflicts of interest that make collective litigation almost impossible. 

Today I will give an overview of surface water law, which governs when a landowner is liable for damage caused by diversion of water to a neighboring parcel of land. 

In California, water that is diffused over the surface of the land and resulting from rain, snow, or springs is known as “surface water.” The mudflows from burn areas are caused by heavy rains on the denuded slopes, and the resulting surface water carries mud and debris downhill. “Surface water” is different from water flowing in a fixed channel (“stream water”), or the extraordinary overflow of rivers or streams (“flood water”).

Three basic rules govern surface water liability in the United States. The first is the “common enemy” rule, which holds that each landowner has an unqualified right to fend off surface water as he or she sees fit without taking into account the consequences to other landowners, who have the right to protect themselves as best they can. In other words, every landowner for himself or herself. Under this doctrine, any landowner may alter with impunity the flow of surface waters to or from adjoining lands.

The cornerstone of the common enemy rule was the ancient property maxim cujus est solum, ejus est usque ad coelum (“Whose is the soil, his it is up to the sky”). The landowner’s absolute dominion over his or her own property gave him or her the right to alter drainage patterns. Resulting damages to neighboring landowners afforded no cause of action. Neighbors could respond only by making improvements or constructing barriers of their own.

The second rule is the “civil law” rule (also called the “natural flow theory”), which is 180 degrees opposite the common enemy rule, and places responsibilities on both the upper and lower landowners to not resist surface water. Based on the ancient maxim aqua currit, et debet curerer, ut solebat es juie naturae (water runs, and it should run, as it is used to run naturally), the civil law rule holds that the lower landowner must accept the surface water that drains onto his or her land (cannot build a dam), but the upper landowner cannot alter the natural system of drainage so as to increase the burden (cannot construct artificial channels that funnel and thereby increase the flow).

Before 1966, California courts followed the civil law rule. However, commentators and courts in many jurisdictions increasingly condemned the rule for hindering land development. Courts also criticized the civil law rule because of the evidentiary burden it presented. It was no simple matter to determine the course and amount of flow before diversion to determine the extent of the damages.

This brings us to the third rule, the “reasonable use” rule, which governs surface water liability today. In the 1966 case of Keys v. Romley, the California Supreme Court held that every landowner must use reasonable care to avoid injury to adjacent landowners, and a failure to exercise “reasonable care” may create liability for the upper landowner. The lower landowner remains responsible to take “reasonable precautions” to avoid or reduce actual or potential damage.

Unlike the common enemy and civil law rules, the reasonable use rule was not born of ancient Roman law. Rather, it is an American original based on tort law. What constitutes a “reasonable” use is determined case-by-case, not by inflexible property right rules. 

In 1994, the California Supreme Court for the first time applied the rule of reasonableness to an inverse condemnation claim in finding a public entity liable, just like a private landowner, for altering drainage and damaging a downstream/downslope property. 

This was an important departure from inverse condemnation law governing cases not involving surface water flow. As you may recall from the first article in this series (MJ #24/4, page 22), inverse condemnation describes the case where the government takes or damages private property but fails to pay the owner, who then must sue the government to recover compensation. Any property damage caused by government improvements is compensable under the Constitution, whether foreseeable or not, as long as the property owner demonstrates a cause-and-effect relationship between the public works and the incident giving rise to the property damage. In general, inverse condemnation is a strict liability, not a fault-based doctrine.

But water is different – inverse condemnation becomes a fault-based doctrine when dealing with damage caused by surface water flows. Liability for damage caused by either public or private property is determined by a rule of reasonableness peculiar to water law. First, if the upper landowner is reasonable and the lower landowner is unreasonable, the upper landowner prevails. Second, if the upper landowner is unreasonable and lower landowner is reasonable, the lower landowner prevails. Third, if both the upper and lower landowners are reasonable, but the lower landowner is damaged, the lower landowner prevails. 

Courts consider all the relevant circumstances to decide whether a landowner acted reasonably. Reasonable care is a question of fact for a jury or judge acting as the trier of fact and all of the relevant circumstances must be considered, such as amount of harm caused, the foreseeability of resulting harm, the defendant’s purpose or motive, and the amount of injury done to other landowners as compared with the value of the devices or improvements that caused a change in water flow.

This fact-intensive, case-by-case inquiry further reinforces the uniqueness of each property and each case. Courts faced with having to make decisions about surface water liability would be impeded by collective litigation, such as class actions, which improperly treats all property owners’ claims as an undifferentiated mass. 

The inquiry is also cross-disciplinary and extremely expert-intensive. An integrated team of experienced technical experts, including hydrologists, geologists, soils engineers, appraisers, and structural engineers are necessary to successfully litigate a surface water case.

A final word. A few weeks ago, I read an article about Arbor Day, which celebrates trees. The author told a parable that seems apt for Montecitoans. An ancient Rabbi, Yochanan ben Zekkai, said: “If you have a sapling in your hand and someone tells you the Messiah has arrived, first plant the sapling and then go out to welcome the Messiah.”

This is the third in a series of articles about the law and the Montecito mudslides. You can read the first two articles on, Volume 24, Issues 4 and 5, or email me:


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