Rainwater used for irrigation

This should comply with the credit, as it is commonly accepted that 100% of TSS is removed when capture/reuse is proposed.

Be careful about the type of filter you use. We used a first flush filter, which essentially took the dirtiest water at the start and it was "flushed" down into the city storm system, which resulted in all of our TSS going down the city storm (but not into the water re-use). Of course the intent of the credit is that you remove the TSS from the water going to the city storm, so this filter and our water re-use didn't do anything to address water quality. We got caught on this on our first design review, but were fortunately able to address water quality with a bioswale instead. Alternatively, if you use a filter that captures the TSS and requires clean-out, or goes somewhere other than city storm, then you are removing TSS from city storm.

I have always just designed a cistern with slightly more volume required. The thought process here is that the TSS settles out at the bottom of the cistern, and this is cleaned out during the dry season. Depending on the means of conveyance to the cistern, you could always add a snout or something similar to ensure the bulk of your WQ occurs upstream of the cistern.