der fall into two optional tiers (see Tables 1 and 2). Each tier includes some prerequisites that must be met. Each tier also requires that a project include a certain number of optional provisions. For instance, Planning and Design has two mandatory measures and 14 electives. In order to satisfy that category’s Tier I requirements, you have to meet the mandatory measures and include two optional provisions. The best way to get an understanding of the overall code is to look at Appendix A4 in Section A4.602 of the regulations. It has a concise table of all the requirements, with descriptions noting which are mandatory for each tier.
The tier structure, although useful, is somewhat arbitrary. Local code jurisdictions can require that all projects meet the requirements for one of the tiers (the simplest approach), or they can cherry-pick whatever they want, such as ten items from Tier I and five items from Tier II. They can enact requirements that are even more stringent than CalGreen. There are also provisions for “Innovative Concepts and Local Environmental Conditions” in each category.
Currently, California’s municipalities are reviewing CalGreen and deciding what portions they want to adopt. Clearly, there is a lot of flexibility beyond the basic mandatory measures. Builders, home performance professionals, and energy consultants are worrying that it’s going to be difficult to track what might be wildly varying requirements in each district. The California Energy Commission has stated that it plans on publishing a database of jurisdictional CalGreen variations, but that will probably take some time to develop.
The CalGreen mandatory requirements are, for the most part, straightforward and not too onerous (with a few exceptions). Many of them are already required by local jurisdictions, or reflect industry best practices or just plain common sense. Table 3 is a summary of the mandatory requirements.
In the Planning and Design category, you have to develop a plan to manage storm water drainage during construction, and a postconstruction surface water management plan. Most municipalities already require both of these, and many rural jurisdictions require erosion control plans as well. To meet the Energy Efficiency requirements, you only have to comply with the Title 24 baseline code provisions. CalGreen explicitly states that its intent is to encourage all new residential buildings to be at least 15% more efficient than Title 24, but it’s not required. The Water Efficiency category requires you to reduce indoor water usage by at least 20% by meeting specific fixture flow rates or doing a simple water use calculation. The flow rates are reasonable—2 gpm for the total of all showerheads in a stall, 1.5 gpm for lavatory faucets, 1.8 gpm for kitchen faucets, and 1.28 gallons for toilets. Irrigation systems require weather- or soil moisture-based controllers.
Material Conservation provisions require sealing all building envelope penetrations. Exterior-plate penetrations are supposed to be sealed with a cementitious material to deter rodents. In addition, a minimum of 50% of construction waste has to be recycled or salvaged. If the local jurisdiction doesn’t have a waste management ordinance, you have to develop a waste management plan and submit it to the enforcing agency. Finally, you have to provide an operations and maintenance manual to the building owner. CalGreen has a list of specific topics that are supposed to be included in that manual.
With 14 mandatory measures, the Environmental Quality category is the toughest to meet. Gas fireplaces must be closed combustion; wood fireplaces must meet expanded polystyrene (EPS) Phase II emission standards. Duct openings have to be sealed during construction to avoid contamination. Adhesives, sealants, paints, carpets, resilient flooring, and interior finish materials like medium-density fiberboard (MDF) and particleboard all have to meet fairly stringent VOC standards. Framing must have moisture content less than 20% before it can be covered. Bathroom fans must be Energy Star la