They're sturdy, they're simple, they're cheap. But block walls, common for basement walls or foundations, are often unsealed. The porous building material, -- concrete masonry units, cinder blocks or other -- easily absorbs dog urine, leaving stains and odor. To keep a block wall odor- and stain-free, remove the stains and seal the wall.
Soak up liquid urine from the concrete with paper towels, changing to fresh ones until the area's dry. Scrub the block wall with the scrub brush to remove dirt, dust and other debris.
Spray the wall with an enzyme-based cleaning spray. The enzymes work to break down urine, removing the stain and odor. An unsealed block wall will absorb the spray, so you need to apply enough to saturate the block. Don't be surprised if you have to spray layer after layer. Cover the block surface with a plastic tarp to reduce the cleaner evaporation. Leave it covered and let the cleaner dry completely. Repeat this step if necessary.
Seal the concrete block wall with a silicate-based concrete sealer by pouring sealer into a paint tray and applying it to the wall with a paint roller or brush. Allow it to dry according to the manufacturer’s directions before applying a second coat. The finished surface should repel urine, making it much easier to clean. Don't let urine stand, though. Wipe it up immediately, and apply enzymatic cleaner to keep pets from thinking the block wall is a urine depository.