The regions that were able to use more green infrastructure are discharging into oceans and have different (higher) levels of allowable discharge/events.
The map you post from the EPA site does not indicate which cities they are, but it looks like precious few of the overall number are discharging to oceans. Certainly Milwaukee is not. Toronto is not. EPA considers downspout disconnects a best management practice - one of many. Here they list some interesting case studies. I am still confused...

Here are some of my notes from the Feb 25, 2009 meeting with NEORSD. Concerns were brought up at the meeting, including:
- why the CSO program wasn't integrated with the stormwater program;
- why individuals couldn't do more (for both CSO and stormwater management);
- could the sewer district provide modeling numbers for rain events, and show impact (or lack of impact) of individual actions

Stormwater management and fees 
The stormwater and sanitary/combined sewers are different programs, addressing different problems, and using different sources of revenue.  Although there is some overlap and potential that the stormwater program could help with CSOs, many (most?) of the proposed stormwater projects are in areas with separated sewers and proposed to correct flooding, erosion and water quality issues - issues that are hard to control through individual action, or where individual action could worsen the problem (see map at link below)

I have posted information given as color handouts at the meeting relating to:
- comparison of stormwater rates by city;
- NEO stormwater problem areas; and
- NEO construction project and maintenance locations (including proposed 2010 and 2011 project locations).

This data is from early 2009 and before, so things may have changed or been updated. I have not seen an updated list of projects. Some of the scans may need to be viewed in large format to see small text, so I would recommend saving them and opening locally as they don't always display properly on the website. http://www.gcbl.org/image-galleries/water/stormwater-management-and-csos

Combined sewer overflows and individual actions
My notes from the meeting indicate that the main problem with individuals doing more as part of the NEORSD program (specifically relating to CSOs) relates to EPA Region 5 standards for water discharge into freshwater. The regions that were able to use more green infrastructure are discharging into oceans and have different (higher) levels of allowable discharge/events.

NEORSD is working under stipulation with EPA that there be 4 or less events per year (an event being an overflow), not actual gallons of overflow per year.  So on the CSO side, their modeling shows they need to capture 250,000,000 million gallons (rough estimate for a 4 month storm) to meet the EPA requirement and provide for possible additional runoff events, and there isn't any level of confidence that this can be done with green infrastructure alone.  

Questions from the meeting:
- It seems to make more sense to regulate the actual amount (gallons) of overflows, instead of the number of events (answer: this isn't the current legal agreement with EPA)
 - Would we rather have 15 smaller overflows or 3 large overflows at 250,000,000 gallons each?  Also, what is being done to actually eliminate CSO outfalls? (answer: some are being eliminated, but many will remain, but just not discharge under projected conditions)

It seems that some of the questions need to be asked of EPA and why they are requiring the current standards for CSOs into freshwater, especially if the community desires more green infrastructure solutions. The downside could be that allowing for more green infrastructure may actually increase the amount of untreated sewage flowing into lakes and rivers. Again, these were my rough notes from almost a year ago.

EDIT:  I also posted a runoff calculation that we did after the meeting for the Museum property.  Using the equation V = Area (sq ft) x Rainfall (feet) x System loss (.9) x 7.5 (gallons per cubic foot), we calculated that a 1" rain event would create over 70,000 gallons of runoff that would need stored.  http://www.gcbl.org/image/cmnh-rainwater-runoff-calculation-example

In this thread, both David and Kyle have suggested that we may call or email them to discuss this. Thank you very much, but I have spoken with both of you privately already and will be glad to do so in the future.

However, I think this conversation belongs right here online where others can join the discussion. That's the beauty of the internet - more voices and no hierarchy - less "behind the scenes". Open and transparent.

Stormwater concerns us all. And don't get me wrong, I agree that we have a massive problem and I am willing to contribute to addressing it and solving it for seven generations. I am just curious as to why it should not, could not be aided by citizen action and not just citizen money.

Kyle,

Since you have determined that we need to hold (and then treat?) or absorb 5 billion gallons of runoff, what are the calculations for the impact of downspout disconnects?

Am I correct in understanding that the huge sums are for storage tunnels and treatment?

From Where does it go?: "to reduce these overflows and to meet epa mandates, the District is building gigantic storage tunnels to hold the overflow until the rains subside and our treatment plants can process the water. these tunnels provide relief for overloaded pipes, which can help local communities alleviate sewer backups and flooding problems"

How did you determine that if municipalities can be convinced that they should change their codes to allow for disconnects and education programs were implemented to have homeowners do so, this would only solve X part of the problem? What would X equal in your study of the issue?

I am just/still curious about how you arrived at the amount of grey and green infrastructure that will be required. It would be interesting to know what the impact of downspout disconnects have been in other communities. Surely NEORSD has gathered this information. In communities that I have researched (Toronto for example - read Staff Report-PDF), they publicly state that treating stormwater that can be absorbed in the property owner's pervious area is costly - too costly.

What will the cost be for treating all this additional stored roof runoff. Since in slighter rain events all my home's clean runoff is presumably treated via the combined sewer system which goes to the treatment plants, you must surely have some idea of the cost of treating runoff vs sanitary sewer outputs. No?

Also, this is an interesting new finding that might have impacts for future water issues and may change the way we have thought about water in the ground for 100 years. Water Hits and Sticks: Findings Challenge a Century of Assumptions About Soil Hydrology

Glad to see stormwater generating a vigorous discussion. We as a region have two big stormwater related issues and NEORSD is leading on both:

1) Five billion gallons per year in remaining combined sewer overflows, and 2) $228 million in growing flooding, erosion, and water quality problems across the City of Cleveland and 61 communities which make up NEORSD’s service area.

We at NEORSD are eager to discuss these issues. Please contact me at 216-881-6600, ext. 6414 or Dreyfuss-wellsK@neorsd.org if you want to talk stormwater. To briefly clarify some points raised so far, I offer the following:

1) Downspout disconnection: NEORSD supports municipalities in allowing this and we will encourage disconnects by offering credits under the regional stormwater management program. We don’t control local ordinances, however, so please remember it is each community’s decision to allow this practice.

2) Disconnection to a rain garden: Disconnecting a downspout without an area available to absorb the water could cause flooding for your neighbor. Please direct water flow to a rain garden or other low lying area of your property where the stormwater can slow down and soak in. If you don’t have such an area, disconnection may not be right for your property.

3) Combined Sewer Overflows: We've made lots of progress, reducing CSOs from 9 to 5 billion gallons. We still have work to do and are looking at all options – grey and green infrastructure - to get the job done with the most benefits to the region.

4) CSOs and downspout disconnection: Downspout disconnects alone can not solve the remaining 5 billion gallons. A broad range of innovative strategies will need to be used in combination. Also, remember there are impervious streets and sidewalks we all share that contribute to the problem and many properties simply do not have enough room to handle all of their stormwater on-site.

Also a few points on the upcoming stormwater program, fees, and credits:

1) Properties – residential, commercial, and institutional – will pay a fee based on the amount of impervious surface (rooftop and driveway).

2) Why a fee based on impervious surface? Impervious surface causes more runoff and more runoff causes flooding, erosion, and water quality problems. The monies generated by this fee will go to fix the current problems and minimize new concerns.

3) Residential properties will be in tiers – small (less than 2000 square feet of impervious surface), medium (between 2,000 and 4,000 square feet of impervious surface) and large (more than 4,000 square feet impervious surface). The fee will be $2.85/month for small, $4.75/month for medium, and $8.55/month for large.

4) Non-residential properties will pay based on their amount of impervious surface at a rate of $4.75/3,000 square feet of impervious surface/month. For example, a commercial building and its parking lot that have 120,000 square feet of impervious surface will pay $190/month.

5) We have measured the impervious surface of properties in our service area using analysis of aerial photography and geographic information system tools.

6) We will offer credits for stormwater control measures – not just downspout disconnects but good stormwater basins, rain gardens, bioswales, and other great ideas - that control a parcel’s runoff and mitigate its impacts on flooding, erosion, and water quality.

I hope that helps clear things up. Please call or e-mail if you would like to talk further.

I think that as the stored ground water and glacial and snow melt reserves vanish, that the land values in NEO will become some of the highest in the nation, if not the world!See if I'm wrong in 30 to 50 years. The storm water tax and the land bank will be an intergal part of this conservation of the natural resourse that will bring the Great Lakes into the forefront in the future. Any and all solutions major or trivial will guarntee this legacy for the next generation. Lete just get it done!!!