The Seattle City Council is expected to pass a set of bills Monday afternoon that will set up 2016 as a year to lay the legislative groundwork for a plan to create 20,000 affordable units in the city by 2025.

Monday’s legislation adds a new chapter 23.58B to the Seattle Municipal Code while amending other portions of the code “to establish the framework for an Affordable Housing Impact Mitigation Program for commercial development.” A second resolution slated for vote by the full council Monday afternoon states “the Council’s intent to make changes to zoning and land use regulations to implement a mandatory inclusionary affordable housing program for residential development and an affordable housing impact mitigation program for commercial development recommended by the Housing Affordability and Livability Agenda Advisory Committee and the Mayor.”

Got all that? The legislative machinations set up the City Council — including some new names… and old — to shape two new programs in the new year.

The commercial linkage fee will require all new commercial development to pay into an affordable housing fund or create an equivalent amount of housing at another site. In exchange, developers that brave Seattle will be rewarded with additional floor area to help builders offset the costs.

Mandatory inclusionary housing will require all new multifamily buildings to make 5-8% of their units affordable to those making 60% of the area median income or require developers to pay into an affordable housing fund. In 2013, Seattle households at 60% AMI took in $40,487.

Here is the timeline for implementation of the new rules.