Natural History. A member of the weasel family, the sea otter is the smallest marine mammal in North America. The southern, or California, sea otter ranges along the coast from San Mateo County southward through Monterey County and down to Santa Barbara County.Unlike other marine mammals, sea otters don't have a thick layer of blubber. member of the weasel family, the sea otter is the smallest marine mammal in North America. The southern, or California, sea otter ranges along the coast from San Mateo County southward through Monterey County and down to Santa Barbara County. Unlike other marine mammals, sea otters don't have a thick layer of blubber.
In modern plumbing, a drain-waste-vent (or DWV) is part of a system that removes sewage and greywater from a building, and regulates air pressure in the waste-system pipes to aid free flow.t the building drain system's lowest point, the drain-waste vent is attached, and rises (usually inside a wall) to and out of the roof. Waste exits from the building through the building's main drain and flows through a sewage line, which leads to a septic system or a public sewer.
The Main Vent Stack. The main vent is stack is often, but not always, a continuation of the soil stack, which is a 3- or 4-inch waste pipe that extends vertically down from the uppermost bathroom to the sewer.ndividual vents must rise above the overflow line of the topmost plumbing fixture in the house before you can tie it to the main vent stack. This is a precaution that prevents the vent from becoming a drain if that fixture's drain gets blocked.