2005 - 2006 - Information Requests Issued: EPA issued information requests to five municipalities in the lower watershed based on baseline data collected by MyRWA which indicated high bacteria levels in the Mystic and tributaries. Information Requests provided more data and led to the issuance of several orders in later years.

2007 - First Annual Water Quality Report Card: The Mystic receives a D as its first Water Quality Report Card grade for calendar year 2006. See grades and related press releases for subsequent years.

2008 - The Mystic River Watershed Initiative: EPA launches the Mystic River Watershed Initiative in order to improve water quality and public access to open space in the watershed.

2007 - 2009 - Administrative Orders: EPA issues Administrative Orders to several lower Mystic River communities to remove illicit discharges from the storm drain system discharging to the Mystic River and its tributaries.

2008 - Administrative Order to Suffolk Downs: EPA ordered Suffolk Downs to immediately cease discharging pollutants being discharged to Sales Creek, a tributary in the Mystic River Watershed. Suffolk now routinely inspects its facility for discharges to Sales Creek and the adjacent wetland and collects limited dry- and wet-weather samples from its outfalls.

2009 - Exxon Mobil Litigation: The Mystic River Watershed received grant funding derived from the criminal sentence imposed in the federal Clean Water Act case against ExxonMobil Pipeline Company. As a result of this case, the Massachusetts Environmental Trust issued $1 million in grants and the North American Wetlands Conservation Trust issued $1,663,150 in grants all for environmental projects to the Mystic River and Chelsea Creek.

2009 - Mystic River Watershed Steering Committee: The Steering Committee was created to allow environmental advocates, state and federal regulators, and business and municipal leaders to work collaboratively to promote actions that will improve environmental conditions throughout the watershed. The Committee is focusing on restoring and protecting water quality, wildlife and its habitats, while also protecting and creating open public spaces for safe public access to the waterfront.

2010 - City of Revere Consent Decree: EPA and the Department of Justice negotiate a Consent Decree with the City of Revere to address Sanitary Sewer Overflows ("SSOs") and illicit discharges, where the City will spend $50M to $100M over the next ten years to address infrastructure problems related to these issues.

2012 - Sterling Suffolk Racecourse LLC Action: As a result of EPA enforcement action under the Clean Water Act, Sterling Suffolk Racecourse LLC (Suffolk Downs) was required to pay a civil penalty of $1.25 million and will perform three environmental projects that provide water quality monitoring and protection. The settlement required the facility to implement green infrastructure and low impact development techniques to address stormwater discharges from the racetrack and maintenance areas of the facility and all construction is now complete.

2012 - City of Boston Consent Decree: EPA and the Department of Justice negotiate a Consent Decree with the City of Boston to address Sanitary Sewer Overflows ("SSOs") and illicit discharges and to address infrastructure problems related to these issues

2013 - Mystic River Watershed Federal Partnership: EPA's Office of Water announces the Mystic River Watershed's designation as an Urban Water's Federal Partnership Location. This exciting partnership reconnects urban communities, particularly those that are overburdened or economically distressed, with their waterways by improving coordination among federal agencies and collaborating with community-led efforts to improve our nation's water systems and promote their economic, environmental, and social benefits.

2014 - Final National Pollutant Discharge Elimination System (NPDES) permits for seven bulk petroleum storage facilities to meet the requirements of the Clean Water Act. On September 24, 2014, EPA Region 1 (EPA) and the Massachusetts Department of Environmental Protection (MassDEP) reissued seven NPDES permits to require wastewater treatment and regulate the pollutant discharges from these seven facilities located along Chelsea River in Chelsea, Revere and East Boston. Along with these draft and final permits EPA conducted several public meeting to enhance community information, participation, and outreach, and issued an Environmental Justice Analysis prepared in support of the permitting actions.

2015 - Improved Grading System: EPA and MyRWA develop an improved system to assign water quality grades to the Mystic River and its tributaries. The increased availability of data allows for segments of the watershed to be assigned individual grades based on bacteria levels instead of one grade to describe all segments of the watershed. This new system indicates that water quality in some parts of the watershed is quite good, while other parts still need improvement.

2015 - EPA launched a Mystic River water quality monitoring buoy in front of the Blessing of the Bay Boathouse in the City of Somerville. The buoy measures a number of water quality parameters such as temperature, dissolved oxygen, pH, turbidity, specific conductance, and chlorophyll that can be viewed by the public in near real time, and data is made available on EPA's Mystic River Website. In addition to providing real-time water quality data to the public, the buoy is used to monitor for and track cyanobacteria (blue-green algae) blooms.

2016 - Phosphorous Loading Studies: EPA and MyRWA with support for USGS and MWRA, begin to examine how high levels of phosphorous, from stormwater runoff, are impacting the watershed. EPA and MyRWA also explore effective ways to reduce phosphorous loading throughout the watershed.

2016 - The main stem of the lower Mystic River earns an A- for bacterial water quality (for calendar year 2015).

2016 - Final Massachusetts MS4 General Permit. In April 2016 EPA issued a final stormwater general permit updating requirements for small "Municipal Separate Storm Sewer Systems" (MS4) located in Massachusetts. The new permit will enhance stormwater management efforts across Massachusetts, better protecting rivers, streams, ponds, lakes and wetlands from pollutants including elevated levels of nutrients, which are causing algae blooms and other problems in many Massachusetts communities. The permit conditions apply to all communities in the Mystic River Watershed. Special conditions for the reduction of phosphorus and pathogen found in stormwater are included in the permit for all Mystic River Watershed communities.