In Armstrong v. Francis Corp., decided in early 1956, the New Jersey Supreme Court abandoned the old Common Enemy Rule and adopted the Reasonable Use Rule for surface water disputes, holding that a developer who alters natural drainage in ways that damage a neighbor’s property may be required to pay for the harm and the fixes.1Justia. Armstrong v. Francis Corp. The case arose as postwar housing tracts spread across rural New Jersey, and it remains a primary reference point when courts weigh a landowner’s right to develop against a neighbor’s right to be left alone.
What Happened to the Armstrong Property
David and Mary Jane Armstrong lived downstream from a large housing project built by Francis Corp. To handle runoff from the new development, the corporation installed a corrugated iron pipe along the path of a natural stream and funneled the water toward a culvert. Rainwater began reaching the stream faster and in far greater volume than it had before.1Justia. Armstrong v. Francis Corp.
After heavy storms, the brook rose in flash surges and left muck and silt as much as 18 inches deep. The redirected flow stripped away about 10 feet of soil from the Armstrong property, and the erosion advanced to within 15 feet of the family’s septic tank.1Justia. Armstrong v. Francis Corp.
From the Common Enemy Rule to Reasonable Use
Before Armstrong, New Jersey followed the Common Enemy Rule, which treated surface water as a foe every landowner could fight without regard for the effects on neighbors. Under that older doctrine, a property owner had an essentially unrestricted privilege to deal with runoff however they wished.1Justia. Armstrong v. Francis Corp.
The court found that approach unsuited to a state where land was being subdivided and built out at scale. In its place, the court adopted the Reasonable Use Rule: a landowner may make reasonable use of the property even if that changes surface water flow, but the legality of any given change turns on whether the utility of the use outweighs the gravity of the harm to others. Reasonableness became a question of fact, decided case by case.1Justia. Armstrong v. Francis Corp.
How Courts Weigh Reasonableness
The balancing test the court described looks at several factors:1Justia. Armstrong v. Francis Corp.
- The amount of physical harm caused to neighboring land.
- How foreseeable the damage was when the work was done.
- The social value or purpose of the project.
- Whether the developer acted with a proper motive.
If a court concludes that a developer could have avoided significant damage through different engineering choices, the use can be found unreasonable. The standard pushes those planning construction to account for downstream effects at the design stage rather than after neighbors are already flooded.1Justia. Armstrong v. Francis Corp.
Who Pays for Drainage Improvements
Justice William J. Brennan, Jr. wrote the opinion and explained why the cost of managing drainage belongs with the developer. Housing construction may benefit the community, but the court held that the price of that benefit should not be shifted onto an individual neighbor whose land is being torn up by the resulting runoff. The developer profits from the expansion and is better positioned to absorb the cost of reinforced banks, better piping, and similar measures. Brennan treated those expenses as an ordinary cost of doing business.1Justia. Armstrong v. Francis Corp.
That cost-allocation principle is the practical legacy of the case. A developer whose project changes how surface water moves cannot leave the resulting damage on a neighbor’s ledger, and the improvements needed to prevent that damage are built into the project’s budget rather than paid for by whoever happens to live downstream.1Justia. Armstrong v. Francis Corp.