Caustic soda and drains?

[robgraham]

Does caustic soda drain cleaner only really work with drains that are blocked with fatty deposits or will it work with a drain that is bathroom and washing machine only ?

I think I'm going to have to bite the bullet and replace a bit of an

80 year old drain from the back of my house as it is developing a blocking characteristic. I have a feeling the problem lies under the area where we park our cars and I reckon is due to compression of the ground over the years which has probably broken one of the couplings, but I clearly would rather not do it at this time of year and wonder if a shot of caustic might help. Any comments?

Yes, I've had the rods down it but there's a 90 degree bend without a rodding eye :>( and the only way to get at it's access cover is to dig, fortunately not too far down, but I don't want to have to continue digging !

Thanks

Rob

[George]

All drains,however throw it down in solid form and flush a bit of water from the taps down..not a lot mind and leave overnight.

[Stuart Noble]

You could maybe drill a hole in the soil pipe near the 90 deg bend big enough to stick a hose in. I had to do that once but it worked where power jetting had failed. Turned out to be an ancient bird's nest that had gradually worked its way down as it decomposed.

[robgraham]

Thanks for the idea Stuart, but I think you're working in the wrong plane - the 90 deg bend is some 7m in the horizontal plane from the rodding eye that does exist. There is then a 30 m run from the aforementioned bend to the septic tank, without any access. I think the problem lies half a dozen metres or so down this 30m run.

Rob

[DIY]

Caustic soda should dissolve soap residue/lime scale from a bathroom and washing machine but whether it would be in contact with the blockage for long enough at a high enough concentration is another matter. In my experience caustic soda works best on small diameter drains. Is there any way of applying pressure and suction at either end of the drain? I cleared a

4 inch diameter drain by using a toilet plunger on the opening - it took many gallons of water and several hours but it eventually cleared. But the drain was only blocked, not collapsed. Otherwise you could think about getting your local water company or a drain clearing firm to put a camera down to see what is causing the blockage, debris or a collapse. Might be useful to know this before you start digging!

[The Natural Philosopher]

Rob, its worth a try. Throw solid donew the nearesrt upstream manhole, and a few kettles of scalding hot.

If it doesn't work, try acid.

Stuff that resists alkalis often succumbs to acid.

If neither works,its dig time.

After such an assault, the septic tank may need a lot of water and some new bugs-in-a-packet to restart its operation..