Why are there suds left in the machine after washing cloth nappies?

Are leftover suds always a problem?

No. You have to know which part of the cycle still has foam. The UK Nappy Network wash guide — written with libraries and makers — wants visible suds in the main wash and none after the last rinse. Their working picture is at least about 3 cm of foam while the wash is actually washing, then a clear drum at the end.

Clean Cloth Nappies (chemist-reviewed, Australia-based, widely used by UK parents) pushes back on the idea that mainstream detergent 'coats' nappies like poison. Their point is that leftover foam is often a mismatch: too much surfactant for the soiling, or a powder in very soft water — not a mystery residue you must starve the next wash to 'detox'.

What should I do when the cycle ends still foamy?

1. 1
   Rinse until the foam is gone UK Nappy Network: if bubbles remain after the final rinse, rinse again until they are gone, to stop product sitting in the pads. Use the extra-rinse button or a rinse-only cycle. Do not add more detergent to a rinse.
2. 2
   Only then change the next dose After a clear rinse, step the next wash down a little if foam was heavy at the end — or up a little if the main wash had almost no foam and the nappies still smell. Always start from the pack, not from a number on a forum.
3. 3
   Check hardness before you 'under-dose for safety' People in hard-water areas often need more powder than a soft-water neighbour. Look up your supply on your water company's checker, then read the pack row for that band. Do not invent a gram figure.
4. 4
   Clean the machine if every load foams A blocked filter or a drawer full of old gel can seed foam into a nappy load. Run the maker's maintenance cycle, then re-test one nappy wash before you throw the detergent out.

Why do leftover suds get blamed on 'detergent build-up'?

Because foam is visible and wee is not. Parents (and a lot of chat answers) see bubbles and cut the powder. The next load then under-washes. UK Nappy Network is blunt that too little detergent, as well as too much, can leave smells — and their 'strip' for either case is a full-dose 60 °C wash in a clean machine, then rinse until every bubble has gone.

Hardness changes how much foam you see. The Drinking Water Inspectorate explains that hard water produces less lather from washing powders. So a South East load can look 'not soapy enough' while still being correctly dosed — and a soft-water load can look like a bubble bath on the same scoop. Read the rinse, not the panic.

MayTally is not setting a hardness cut-off or a scoop size. Official hardness bands live on the DWI page; your number lives on your water company's postcode checker; your grams live on the box in your cupboard.

How does this sit in a normal UK wash routine?

UK Nappy Network's skeleton is: dry-pail, a separate cold rinse, then a long 40 °C or 60 °C cotton-type wash with a full dose of (usually) powder, extra water if the machine has it, no fabric conditioner, then line dry. Which? also says wash at least every two days and skip conditioner. Suds troubleshooting is the last ten minutes of that routine, not a new chemistry hobby.

The NHS says there is no evidence that bio powders or fabric conditioners irritate a baby's skin. That is a skin statement. For cloth absorbency, NHS changing advice and Which? still say not to use conditioner on cloth nappies. Suds are about rinse and dose, not about switching to a 'baby' liquid.

When is a foamy rinse a strip-wash job?

If extra rinses clear the drum and the next adjusted wash stays clear, you do not need a strip. If nappies still smell of wee or hamster-cage when clean, or every rinse is a bubble bath after you have cleaned the machine, UK Nappy Network's isolated reset is: clean machine, full-dose 60 °C, then rinse until all bubbles have gone. Skip internet recipes that add vinegar, washing-up liquid or bleach — the same guide lists those as things makers tell you not to use.

In shortIn short: foam during the wash is useful; foam at the end needs more water now and a small pack-based tweak next time. Do not starve the next load because bubbles looked scary. Hardness and soiling change the picture — check your water company and the box, not a guessed gram.