4 Waterfall Lane, off River Road in Cos Cob, is a nifty little place that really does have its own waterfall and backs up to conservation land. It sold for $730,000 in May of ’02, again in April ’04 for $879. Last year its current owners, after “renovating” it ( a flexible term in real estate) listed it for $1.125 million. That must have been pushing the envelope too far because no one bit; today it’s been marked down to $930,000. What’s its proper price? We’ll know once it sells.