Blocked drain: causes, safe DIY clearing, and when it is the building

A blocked drain in a Nellore home is almost always one of four things: hair and soap under the bathroom floor trap, grease and food in the kitchen line, a blockage or collapse in the outside drain, or a building-level problem that no amount of plunging at your end will fix. The first two you can usually clear yourself in ten minutes. The third needs a plumber with a snake or a jetting machine. The fourth needs the landlord, the apartment association or the municipality, and the sooner you recognise it the less you spend poking at your own pipes.

Start by working out which one you have. It takes a minute and decides everything else.

Which block is it?

• One fixture slow, everything else fine. The trap or the short run directly under that fixture. DIY territory.
• Two fixtures in the same bathroom slow together. The branch line where they join, behind the wall or under the floor. Sometimes DIY, often a snake.
• Bathroom and kitchen both backing up, or water rising in a floor trap when someone else in the house uses water. The main line. Call a plumber.
• Water rises in your ground-floor trap when upstairs flats use water. The building's stack or the inspection chamber outside. Not your pipe; not your fix.
• Bad smell but water drains fine. Not a block. Usually a trap that has dried out, covered in our monsoon guide.

Safe DIY clearing in the bathroom

1. Lift the floor trap grating (the jali). Underneath is a mat of hair, soap and sometimes a sachet. Pull it out with gloves, a bent wire or an old toothbrush. This alone fixes most slow bathroom drains.
2. Pour a bucket of hot tap water — hot, not boiling, because most house drains are PVC — down the trap. Soap softens and moves.
3. If it still drains slowly, use a plunger. Hold a wet cloth over any overflow or second opening so the pressure goes down the pipe, and pump hard ten or fifteen times.
4. A hand snake (a few metres of flexible spring from any hardware shop) fed down the trap and turned will reach a hair block in the branch line.

If it still drains slowly after that, stop. The block is further than you can reach, and the next step is a machine.

Safe DIY clearing in the kitchen

Kitchen blocks are grease, rice, tea leaves and vegetable peel. Hot water with a spoon of dishwash liquid down the sink at the end of the day keeps the line moving. For a slow sink, look under it: most have a bottle trap that unscrews by hand. Put a bucket under it, unscrew, clean out the sludge, refit and run water to check for drips. If the block is past the trap, a hand snake reaches a little way; past that, it is jetting.

Do not pour used cooking oil down the sink, ever. In a Nellore summer it flows; by the next cool morning it has set in the pipe.

What not to pour

Skip the concentrated acid sold loose at hardware shops. It heats PVC, weakens solvent joints, and can spit back when it hits standing water. It also sits in the trap waiting for whoever opens it next — often the plumber you then call. Baking soda and vinegar is harmless but does very little beyond a fizz. Hot water, a plunger and a snake do the real work.

When it is a building problem

The signs: more than one flat affected, water coming up through a floor trap or gully outside, an inspection chamber lid that is wet around the edges or lifting, or a drain at the compound wall that is overflowing. The block is in the shared line and it will keep coming back until it is cleared at the chamber. Tell the owner or association; clearing your own trap buys a day at most.

During the north-east monsoon, stormwater in low-lying parts of the city and the coastal side backs up into house drains. That is not a block at all — it is the outfall being underwater. It clears when the rain stops, and nothing inside the house fixes it.

What a plumber does and what it costs

A blocked-drain call on our rate card is ₹399: snake, jetting where the pipe allows it, and cleaning the trap properly. The technician should tell you where the block was and whether it points at something bigger — a sagging pipe that collects silt, a root through a joint, a chamber that needs the association. If the block is in the building main, they should say so rather than clear your end and leave you to book again next week.

Keeping it clear

• A hair catcher on the bathroom grating; lift and clean monthly.
• No oil, no rice water with grains, no tea leaves down the kitchen sink.
• A bucket of hot water down each floor trap once a month.
• If your building's chambers are opened and cleaned once a year, slow drains become rare. If nobody knows when that last happened, raise it.

When to call

Water rising rather than draining, a block that comes back within a week of clearing, more than one fixture affected, or anything where you have already used a plunger and a snake — those are the calls worth making. A single slow floor trap is usually ten minutes with gloves.