California was the first state to pass a bill, signed by Governor Arnold Schwarzenegger, to phase out the use of the incandescent bulbs by 2018. The bill aims to establish a minimum standard of twenty-five lumens per watt by 2013 and sixty lumens per watt by 2018.
The federal government then passed the Clean Energy Act of 2007 which was signed into law on December 19, 2007. This legislation bans incandescent bulbs by January 2014 that produce 310 - 2600 lumens of light. Bulbs outside this range (roughly, light bulbs currently less than 40 Watts or more than 150 Watts) are exempt from the ban. The legislation also exempts several classes of speciality lights, including appliance lamps, "rough service" bulbs, reflector "flood", 3-way, candelabra, colored bulbs, and plant lights.
In December 2007, The United States enacted the Energy Independence and Security Act of 2007, requiring all general-purpose light bulbs to be 30% more energy efficient (similar to current halogen lamps) than current incandescent bulbs by 2012 to 2014. The phase-out will start with 100-watt "general service" bulbs in January 2012. 60 and 40-watt "general service" incandescent lamps are targeted to be phased out by January 2014. By 2020, a second tier would become effective; which requires all general-purpose bulbs to be at least 70% more efficient (similar to current CFLs).
Both California and Nevada have the option of adopting the federal law a year early, and in the meantime, California has already enacted its own standards that reduce the maximum wattage of common incandescent bulbs by 5% while maintaining lumen output.