R801.3 Roof Drainage - "In areas where expansive or collapsible soils are known to exist, all dwellings shall have a controlled method of water disposal from roofs that will collect and discharge roof drainage to the ground surface at least 5 feet (1524 mm) from foundation walls or to an approved drainage system."

"Saturated expansive or collapsible soils can lead to foundation failures because their additional loads are imposed on the foundation wall. To minimize the potential for the soil adjacent to the foundation wall to become saturated due to roof drainage, the code requires that the roof drain 5 feet (1524 mm) from the foundation."

2.2.4 Install drip edge at eave and gable roof edges.

2.2.5 Install gutter and downspout system to divert water at least 5’ away from foundation and from there into the overall onsite drainage area.

1.1 Design and install of rainwater harvesting system which includes the collection of surface and roof run-off for irrigation uses. (1 Point)

4.1 Prepare a detailed durability plan per the design process in Exhibit MR4-A.

4.2 Verify implementation of durability plan via third party inspection as described in Exhibit MR4-C.

The synergy between durability, energy efficiency, and indoor air quality are inextricably linked in high performance homes. Moisture management becomes more critical as energy management reduces the buildings overall drying potential.“
Moisture can be a major cause of indoor environmental problems (e.g., mold)”. The point value of this credit therefore reflects the related indoor environmental benefits of improved water management at the foundation, exterior walls, and roof.
Water management of the property (i.e., both lot and structure) is a combination of surface and ground water management, with the dual goals of protecting the structure from water as well as keeping as much water as possible on the site in order to limit the burden on municipals infrastructure, recharging the aquifer, etc. To the greatest extent possible, the site and landscape should be designed with these goals in mind. The durability plan is intended to prevent damage to the home by water - both surface and ground - that can not be effectively managed at the site level, as well as to protect the structure from other damage functions.
USGBC Rationale is that durability problems can substantially shorten the life of assemblies, systems, and/or materials in a home and indeed the home itself. While the development and implementation of a durability plan can not guarantee improved durability, there are a number of precedents in the insurance industry, in particular, supporting the premise that a prescribed process aimed at improving durability can indeed correlate to improved performance, as measured by decreases in warranty claims for durability-related building defects and failures.