Gurgling drains

[nitgel]

When my washing machine and sink drains it makes quite a loud gurgle, this happens upstairs too. Is there anything I can use to clear or remedy?

I have tried: Mr Muscle sink unblocker, Soda Crystals, plunging and thos very long wires that unblock things. Lastly I have tried caustic soda but it's still gurgling.

Anything else I can try before calling the professionals?

hmm, when this happened to us - we ended up with a blocked drain and toilet paper and sewage all over the garden. It was about £300 worth of work to fix it - mostly due to the fact the previous owners hadn't put any manholes in. MIght be worth getting the experts in if nothing you have tried has worked.

I know the outside is ok as I checked under the manhole cover

Bicarb followed by neat white vinegar. Leave for a while. Poor down a kettle of just boiled water. Repeat til it clears

You need a proper chemical reaction. Soda crystals do basically nothing.

Check with the neighbours to see if they have the same problem. If they do it could be further down the system in the main sewer if they do.
Water companies sewer teams are allowed to open the manholes in the highway and are responsible for their maintenance. They will probably do private drain (your responsibility) clearance for a charge.
Private drainage companies (like Dyno Rod) can only deal with the private drains on your property and can't touch the public sewer.

Has this always been the case or has it just started to happen? Has anything changed in your plumbing recently.

I had this and it turned out it was a broken Air Admittance Valve .

I think I have just started to notice it a few months back.