Do you full time landscapers always do a perk test? I know most of my areas and where there is a lot of clay and where there is not, so i take proper measures to ensure the clay content at some houses doesn't negatively affect the plant or tree's growth. I have a customer who has had a major water drainage issue since i installed a rather large landscape to his back yard around a big patio last season. Most i know was a direct cause of his new irrigation system severely over-watering the garden and flooding out dozens of plants. A perk hole should "hopefully" drain in about 4hrs or less, I have never stayed onsite to watch these holes, but with his sprinklers on each night i assume, the following day, by noon time even, the hole is still 75% filled with water. Roots have become stagnant and trees have died, sometimes groups of them. When the initial job was done, there were 2-3 pipes installed over two areas that are about 30ft wide. I don't think they work though because the holes that were dug for each tree planted, do not allow the water "out" of the potting hole to drain into the drainage and out away from the garden. I've had to install drainage pipes on a few trees in the corner directly connected to the root ball areas to alleviate the buildup of water sitting in the potted holes. Ive even raised up numerous trees, especially all that were replanted with sand and crushed stone underneath to elevate them at least 6" taller so they're not sitting in the water. Apparently, now the customer is claiming more trees have died and still has invoices due that ive billed him for "supplies only" for tree replacements and more drainage install costs. I have not even charged him for any labor involving this initial design plan for the tree replacements, stone/sand delivery etc. He claims that if i did a perk test prior to installing the original landscape design in 2006 that this wouldn't be happening. He may be right, but not all areas don't perk. The area is roughly 1300sq. ft in size and a few spots, maybe only 300sq. ft. of it, have problems, mainly near the center of his large patio, the far corner, and immediately off the corner of the driveway. What else could be done, at least at this point, besides digging all the plants back out, excavating 40-60 tons of non perking clay, paying to dispose of it, trucking in that much top soil grade dirt and organic matter, replanting everything, and re mulching? What makes this almost impossible though is that he has numerous irrigation sprinklers run all over the place in the garden beds that I installed last year. Im thinking aside from him over watering, since we know the soil doesn't perk at all in some areas, is it possible that whomever did his patio work the year prior disposed of the soil they excavated, around the patio right there i installed the garden?