Zoning and other regulations around Falls Lake could lead to a tragedy of the commons at the 770 square mile watershed, recreational area, and water supply source in the Upper Neuse River Basin. In an effort to control land-use by private owners around Falls Lake, Wake County required building lots of one and two acres, much larger than those in the typical Wake neighborhood. The large lot sizes were conceived as a way to limit the amount of “hard surface” in the watershed—from buildings, roofs, and driveways—per acre, a factor in the effort to control soil runoff into the Lake during periods of heavy rain.
Unlike other parts of Wake County, where three or four single-family homes per acre are common, the county limits homes to one per acre in Falls Lake. Within a half mile of the lake, there is a two-acre minimum lot size per home. Zoning has succeeded in making lots much scarcer around Falls Lake than they otherwise might be. The result? The high price of building lots has given owners an incentive to build much larger homes (News&Observer archive, 1/3/05: “Zoned lots beget super-sized houses”) than planners expected. Some homes are so large, in fact, that the Watershed Protection Council is concerned about soil runoff into the Lake, and the destruction of drinking water and other uses of the watershed. If this occurs, it will be a “tragedy of the commons.”
A tragedy of the commons arises when a commonly-owned resource is depleted or ruined for future use because it is in no one’s personal interest to preserve and maintain it. The classic example relates the story of sheep grazing inside a town “commons.” Sheep can overgraze a grassy area, eating right down to the roots of the plants; so the extent of their grazing a single area must be controlled, or the grazing area is ruined for future use. But when no one “owns” the commons, everyone has an incentive to allow their sheep to graze first and as much as they want, since it is likely that there will be nothing left for latecomers. Thus the commons is destroyed for everyone’s use.
Falls Lake Watershed managers fear that if the combined horizontal surface area of roofs, buildings, and driveways in the developed areas exceeds 12 percent of the lot size, or 6 percent for those close to the lake, runoff and soil erosion will destroy the watershed for purposes of drinking water, wetlands preservation, and recreation. They should have anticipated the preference for huge homes, however.
Large lot size and fewer total building lots are factors that have encouraged building the 6,000 to 10,000 square foot homes in neighborhoods around Falls Lake. They aren’t the largest examples. Some homes of nearly 17,000 square feet have been built in the watershed. By comparison, Wake County planners anticipated homes in the 5,000 square foot range. But when owners pay upwards of $120,000 for a lot, they justify that cost with large and expensive homes to match. As a result there is a lot more house and hard surface on each lot than was originally expected.
Whether the watershed is in any real danger as a result of home building is unclear. Builders claim that the county ignores park and other land on which no building will ever occur when it measures the percent of runoff-prone surfaces relative to other areas. What is clear is that landowners have an incentive to continue to build larger rather than smaller homes. Because Falls Lake is a publicly owned watershed, any harm that results from overbuilding will be paid for by taxpayers or families others than the homeowners themselves. This encourages the preference for giant home size that planners fear will harm the public watershed.
The trend toward large homes in Falls Lake is likely to continue. It is such a mark of prestige (and value) in a neighborhood to have large homes, that most exclusive developments set minimum rather than maximum square footage restrictions on new building. People don’t want to buy into an exclusive neighborhood for the privilege of putting up a modest house. Requiring smaller homes in Falls Lake would reduce the appeal and value of living there, and could affect existing home values, albeit in ways that are somewhat unpredictable.
Finally, private owners handle the management of ponds, lakes, and other waterways in a manner that doesn’t require zoning for maximum size homes, minimum size lots, or other arbitrary standards. In the agricultural microcosm of my neighborhood, homeowners who find that their ponds are becoming overgrown with aquatic weeds, for example, take measures to correct the existing problem and prevent new ones. In the extreme, they may have to drain, clear, and reline the pond before they can get rid of the noxious weeds. I have known homeowners to introduce weed-eating koi fish, or use chemical treatments to control the plants. If the source of the problem is runoff from a neighbor’s excessive fertilizer use, it is often possible to observe and remedy, all without new regulation or arbitrary controls. Homeowners take personal responsibility for these measures because the quality of their pond directly affects the market value of their property.
If homeowners on Falls Lake had personal rights as well as financial obligations toward the management of the watershed, they would also face the powerful incentives of personal loss or gain. Wake County created the incentive to build mammoth homes, and to disregard the possible effect of building materials or paved square footage. Since regulation and a commonly owned resource effectively separate the benefits from the full costs of living at Falls Lake, the most likely course for future events will be more regulation, or more super-sized homes.