Thanks guys! It seems that the builders plan in 1974 was for the drainspout runoff to go to the street and to the right side of the photo. Then sidewalks were installed down the hill and around a curve, and they are sloped so the side against the curb is lower than the curb. Error? Sunk? idk. Then the 4 ft high berm added by our neighbor trapped the runoff. Our soil is dense clay and there isn't an easy exit for the runoff. During and after several rainstorms since we dug the giant trench I observed the runoff and smushy tested the lawn to be sure that the downspouts are the problem, and yup, seems to be. Following guidelines from Penn State Extension, the trench with rocks on the bottom and a few plants (carex?) should solve the problem for our average rainstorm, but for a large storm i need to protect the bldg foundation and send the runoff forward, I think having the lawn from the trench to the street lower that the garden from the trench to the building will d that. But you are right Angel18432, it would be better to be just lower and not graded to the ditch. Thank you. also love how the bamboo looks, i will look into that. I cant believe I was so dense,of course -"do not block doors - emergency exit", maybe add arrow to correct addresses. ugh. Yes, the lighting needs work. Yardvaark, I have re-formed and adjusted for changing conditions many of grassy swales and dug what you are describing in another area to control large storm runoff, but the excess has a good way out. I thought that I couldn't do the same here as this area gets wet every storm and will be too smushy, like the areas I want to fix are now. And i didnt know how to improve curb appeal working around a big area smushy most of the time. Rain garden? mulch? floating around? plain dirt? all ground cover? time to establish in wet clay soil? grass? how to mow it? grass clippings with seeds all over? at least 10 ft from bldg? what to do in between? doors have to be accessible to each walkway, esp to move large items. I know you feel natural is best, and you have opened my eyes to that and gardening vs landscape, but I don't know how to do it here. If I am thinking wrong and missing the obvious, please let me know! I did change most of the area from the bldg to the 10ft area to mulch, cut down the yews, will be diligent about tapering other shrubs.

No idea the water source based on photos. A paver patio is built on granular material that drains quite well. so there is no need for a drain under it. Even if the material under it becomes saturated, the patio surface will still shed water, and eventually the saturated material will still drain. The rocks around the edge I would not call a retaining "wall." They act more as a curb. But since the curb is comprised only of individual rocks separated by soil, it, in itself, is not capable of preventing water from draining away. Nor should it be. The existence of the patio & curb seems separate from the problem of an unknown source of water infiltrating an area. (Other than that they could complicate the diagnosis and repair.) But it is enough water to look like a leak ... unless you happen to have a very high water table. If you do and there has been a lot of rain in days prior, that could cause such a condition.

My parents dug out their back yard kind of like this in Salt Lake City Utah to allow for full Southern sun exposure for a passive solar home. The house is not the lowest point and has a few steps going from the back door down to a patio. So there's a small very gentle slope from the patio up to the house. However, there have been 2 incidents in the last 35 years where huge rainstorms combined with nearby irrigation canals have caused flooding. The second incident was just last summer and we had to get some emergency pumps to save their finished basement. Since then they have purchased some pumps to have on hand in case of emergency. If the lowest point and the patio had been even with the basement like your second photo, the water would have been 2ft deep and would have gone into the house.

Triplicate post. https://www.gardenweb.com/discussions/6248813/patio-drainage-help-please#n=1 people need to see a photo to help understand the issue. you can use ghe photo icon to add a pic to your original post.