If the whiff of something unpleasant has you wrinkling your nose in your backyard, or if you’ve noticed standing water that doesn’t seem to drain away, it’s time to turn your attention to your septic system. These are telltale signs that your septic system might be failing.   However, not all signs are as obvious or, frankly, as uncomfortable. Some are subtler and may only be apparent to a trained eye. For instance, bright green, spongy lush grass over your septic tank or drain field, even during dry weather, can also indicate trouble brewing beneath the surface.