Cut the potatoes lengthwise into fairly thick wedges (1/2" to 3/4" thick). Place them in a 9"x 13" casserole dish.
Whisk together the water, lemon juice, oil, garlic, oregano, salt and pepper. Pour the mixture over the potatoes, turning to coat them evenly.
Bake in a 350ºF oven, uncovered, turning occasionally, to keep the potatoes well moistened. Bake for two hours, or until the potatoes are tender and most of liquid has evaporated.