Real Life Question Re Toxic Algae

[PseudoScienceTeach]

We have a typical city backyard 15 x 20 with a little soil and a block wall in the back. The neighbor behind had a long-running leak that caused what we thought was mold growth but turned out to be algae. Is anyone aware of any articles regarding toxic algae growth in a yard/ block fence? Any input. I read about toxic cyanobacteria, but the information focuses on bodies of water. Know of any labs that test toxic algae. Thank you

[pharrast]

This is a forum for help with science projects, so I don't know how helpful anyone here will be. Is the 'leak' just water?
If you have no reason to suspect sewage or chemical contamination, it is probably a normal type of growth that one would find anywhere with constant water available. If you have concerns about contamination in the water, I recommend you reach out to your local water utility. But again they will probably reiterate that regular algae likes water, and grows in it all over the world with no effect on human health or safety