How do I stop increase of flooding & water retention in my back yard?

Plant weeping willow trees if they grow in your zone! They literally suck up your kind of water and grow very quickly. Privacy, shade and no more water problem!

Hi Danita, they changed their grade and now you have the problem, you can create a dry creek bed to deal with it and it will look nice, here is some instruction for you,

https://www.thespruce.com/build-dry-creek-beds-for-landscape-drainage-2132745

You could plant bushes it will absorb the rain water coming from there side

you need to have trenches or french drains installed to direct flow of water from along property lines down to street away from houses.when they excavated to pour cement it pushed earth up so it has higher grade to it causing more water to flow onto lower ground your yard.you cannot force water to go where it doesn't want to only work with it. fastest lowest cost solution Trench. Willows are good for "sucking up water" but should not be planted near homes or structures where there are sewage pipes and water lines because the roots will damage them seeking water,as well as foundations.