Signs of a Main Sewer Line Clog: How to Tell It's More Than One Drain

The clearest sign of a main sewer line clog is that more than one fixture is affected at the same time, especially the lowest ones in the house. Water rising in a basement floor drain or shower, toilets that gurgle when another fixture drains and sewage odors near floor drains all point to a blockage in the main line rather than one branch.

When you see those signs, stop running water and avoid flushing. Every gallon you send down has nowhere to go but back up through the lowest opening in the house.

Your home's plumbing is like a tree. Each sink, tub and toilet has a branch drain that joins larger pipes, which all come together in the main building drain and then the sewer line to the street. A clog in a branch affects only that fixture: a slow bathroom sink, for example, while everything else works normally.

A clog in the main line affects everything upstream of it. That is why the warning signs show up in combinations. If the kitchen sink, a toilet and the tub are all slow, or if using one fixture causes trouble at another, the problem is probably downstream of where those branches meet.

Multiple slow drains. Several fixtures draining slowly at once is the classic sign.

Water in the lowest drain. A basement floor drain or shower that fills with water, especially when the washer drains or a toilet is flushed upstairs, means wastewater is backing up from below.

Gurgling. Air trapped by a blockage can make toilets and drains bubble or gurgle when other fixtures run.

Odors. A sewer smell near floor drains or the cleanout can mean waste is sitting in the line.

Toilet water moving on its own. If the bowl level rises or falls when you run the tub or washer, the shared line below is restricted.

Stop using water in the house, including the washer and dishwasher. Keep people and pets away from any wastewater, which can carry bacteria. If you have an outdoor cleanout and can open it safely, a pipe full of water there suggests the clog is farther toward the street.

Check with a neighbor or two. If they have the same problem, the public main may be involved and you should call Loveland Water and Power at 970-962-3000. If it is just your house, the clog is most likely in your own line, which a City of Loveland newsletter treats as the homeowner's responsibility. For backups that cannot wait, our page on emergency drain service Loveland covers what to expect when you call after hours.

Main lines usually clog for a handful of reasons: grease that hardens on the pipe walls, wipes and other items that should not be flushed, roots growing into joints of older pipe, and pipe that has shifted, cracked or sagged. In Loveland, expansive clay soil, older clay and Orangeburg pipe in older homes, and mature trees all add to the list.

Knowing the cause matters, because it decides whether a single clearing will solve the problem or whether the clog will come back. That is why a camera look after clearing is worth asking for, especially for a second or third backup.

Sometimes the trouble is not in your line at all. During the September 2013 Big Thompson flood, the river ran at roughly 500 times its seasonal flow, more than three square miles of Loveland flooded and flooded sewer lines disrupted the city's wastewater pumping. That was an extreme event, but it shows that heavy flooding can affect the public system.

If backups hit several homes at once, report it to the city. Homes in the Big Thompson corridor, described on our Mariana Butte Loveland drain cleaning page, are a reminder that what happens at the river can matter to the pipes.

A main line clog will not fix itself, and it usually gets worse each time water is used. The quickest path back to a working house is to have the line cleared, then find out why it clogged so the same thing does not happen again next month.

Loveland Drain Clean is a free referral service, available 24/7. Call (970) 693-9705 and we will connect you with an independent local provider who can clear the line and explain what caused it. Providers set their own prices, so ask about rates and timing when you are connected.