Detergent

This is Dulcinea, beating a load of a friend's jeans. All those suds? That's detergent. Detergent that didn't wash out of his clothes when he washed them.

Any papermaker worth their sizing knows this. You only need the barest amount of detergent - in fact, you can sometimes skip it. Detergent not only stays in the fibers of your clothing (where, in my case, makes me itchy all day), it builds up in your washing machine.

By the way, I scraped suds off the top of this load SEVERAL TIMES.

Washing machines and dishwashers are made to use far less water now than older models and, therefore, need less soap. And detergents have also become increasingly concentrated. So a little goes a long way.

“Most people use 10 to 15 times the amount of soap they need, and they’re pouring money down the drain,” Mr. Schmidt said...

... “If people see suds, they think their clothes are getting clean, but that’s wrong — it means you’re using a lot of extra detergent,” Ms. Notini said.

Here is Mr. Schmidt’s test to determine if you’re oversoaping. Take four to six clean bath towels, put them in your front-loading washing machine (one towel for a top loader). Don’t add any detergent or fabric softener. Switch to the hot water setting and medium wash and run it for about five minutes.

Check for soap suds. If you don’t see any suds right away, turn off the machine and see if there is any soapy residue. If you see suds or residue, it is soap coming out of your clothes from the last wash.

“I’ve had customers that had to run their towels through as many as eight times to get the soap out,” Mr. Schmidt said, who lives in Indiana.

(Source.)

Laundry detergents contain sodium triphosphate, which causes eutrophication. Green laundry detergents do better, but maybe, also, consider using less laundry detergent?