Most episodes center on the small businesses and houses surrounding the village pub, Y Deri, and local farm Penrhewl. In addition to the native characters, the show also features incomers from across Wales, with various accents and abilities in Welsh, and even the occasional sais wandering in from England and looking around in terror.
Pobol y Cwm provides examples of the following tropes:
- Babysitter from Hell: One child's regular babysitter slaps him, and steals money and alcohol from the house. She coldly blackmails the boy into not telling his parents until he develops night terrors and bed wetting.
- Blackmail: One 2023 storyline involves Tyler stealing an expensive bike from another villager and trying to resell it. His housemate Mark discovers this and is about to report Tyler to the police - until Tyler threatens to reveal that Mark’s been smoking cannabis to manage the pain from his injured leg, a revelation that could cost him his job even if he wasn't prosecuted.
- Dancing with Myself: In one 2023 episode, newcomer Alaz wanders into the village shop to find shopkeeper Colin dancing around with his headphones in.
- Drugs Are Bad: Nationwide money laundering schemes are nothing compared to one accidental tablet of ecstasy.
- Eloquent in My Native Tongue: When Alaz arrives in 2023 he speaks very little Welsh... and very little English. The villagers tend to use a little more English than usual, sometimes in a bid to help him improve his Welsh.
- Good Girls Avoid Abortion: Played straight and averted. Gaynor makes the right choice for herself, but errs when she lies to her partner about the pregnancy and abortion, and tries to manipulate others. Teenager Lois wants to keep her baby, and the changes it will mean for her relationships and education are discussed. The show spells out clearly that advice should come from medical professionals (contact information is provided on the website) and not internet blogs.
- Hide Your Lesbians: Averted. Three members of the leading cast are out and the show featured a marriage storyline, same-sex civil unions being legal in the UK.
- Line-of-Sight Alias: When Mark and Colin get Cwm FM to host a radio call-in contest to vote on the name of their comedy act, each of them calls in himself to vote for the name he favours. Mark disguises his voice and puts on a fake Northern accent, claiming that he's calling from Anglesey. He is, in fact, standing right outside Y Deri, so when Jinx asks him his name, he comes up with "Elis Maenan" from the signs he sees in the street (for Tomos ac Elis and Apêl Maenan). When pressed, he admits that he's not actually from Anglesey; his eye falls on the sign above the fish (pysgod) and chip shop, and he says he's originally from Dinbych y Pysgod…which, being in the far southwest, doesn't match the accent at all.
- Long Runner: Pobol y Cwm launched in October 1974 and is still going as of February 2023. It also follows the usual British soap opera model - so isn't structured into seasons with breaks between them, and normally broadcasts more than one episode each week. As of 2022, there have been over 8,000 episodes broadcast.
- Scare 'Em Straight: In one 2023 storyline, Garry Monk discovers that Tyler's selling stolen goods and thinks he's also stealing stock from Garry's takeaway, MFC. They have a short, very blunt conversation about it - which ends with ex-crook Garry holding Ty’s head just over a deep fat fryer and telling him why it's never going to happen again. Subverted in later episodes as Garry's business is still crooked and he keeps finding illegal ‘jobs’ for Tyler - it's just that he wants him too scared to steal from Garry himself.
- While looking for work in a 2023 episode, Gaynor complains that all she's done since returning from Thailand is watch Midsomer Murders - and can always identify the killer within a minute or so.
- When Tyler's obsessively looking at his phone in a 2023 episode when he should be working, his employers accuse him of addiction to Wordle. He's actually trying to negotiate his way out of trouble with local crook Garry.
- Stigmatic Pregnancy Euphemism: Lois' mother, the village headmistress, keeps her out of school with "glandular fever" when she gets pregnant. Once classes end for the year, she's too busy "revising for her exams" to see friends.
- Straight Gay: Scott and Alun, both in the closet.
- Villains Out Shopping: Garry Monk's been a thug and a criminal (as of March 2023, he claims he's trying to stay out of trouble and run an honest business, but that's not quite true), but he's also a loving father.