Students living in housing with mould, bed bugs and rats are still seeing their rents go up as campaigners call for controls on how much landlords can charge tenants.
"We had bedbugs, which we paid to have fumigated ourselves out of our own pocket because it was unliveable, and we couldn’t move in until they were gone," Cardiff student Megan Haf said.
Campaigners said rent controls in Wales would ensure people were not being "ripped off" by those who supply accommodation.
The Welsh government said it was considering introducing new legislation on fair housing, and said there was a "need for better data on rents and affordability".
Although house prices in Wales have fallen slightly over the past year, figures from the Office for National Statistics (ONS) showed average rental prices in Wales increased by 9% over the same period.
And the capital has seen rental prices rise by an average of 13% in just a year, with a warning that student housing may be particularly vulnerable to price rises and poor living conditions.
Average rents in Cardiff are now more than £1,000 a month for the first time.
Megan, 21, lives with four other Cardiff University students in Cathays and said they have had numerous issues with their house since moving in September.
"Come Christmas time, we noticed that mould had started to appear [which has] worsened quite rapidly, especially in our bathroom where there’s no window," she said.
Their most recent problem has been rats, and Megan said there had been a "lack of urgency” from their landlord in dealing with the issue.
"Nobody wants to be in the house, and we’re constantly having to find places outside the house to work or even to eat now," she added.
Megan and her housemates will now be moving to a more expensive rental property in the summer.
"But at this point, I don’t mind – they can take my money as long as I get a nicer house," she said.
BBC Wales contacted Kingstons Residential for comment regarding the issues raised by Megan.
Elin Griffiths, 20, is another Cardiff University student who said her accommodation had been affected by bathroom leaks and mouldy walls.
"It is really frustrating," said the third-year medical student.
“We’re finding it really difficult to live in these conditions, especially in the winter when we’ve been getting chest infections.”
Having lived in the same house for two academic years, they were also aggrieved to see their rent go up last year without improvements being made.
"We’re paying more than last year, and the standard of the house has just got worse and worse," said Elin.
"It just seems like they’re not taking our problems seriously at all."
Having found a new place to move to later this year, Elin and her housemates also noticed rising rental prices.
"Most of the houses now are around £500 per person, and a lot of these houses are six to eight people as well," she said.
In response, CPS Homes said, "The landlord, together with his contractors, haven’t been quick enough or effective enough" in responding to issues at the property.
The letting agent added it had only recently been given the go-ahead to make improvements on the landlord’s behalf, which had now resulted in "a great deal of work" being completed.
The landlord has been approached for comment.
Deio Owen, vice-president of Cardiff Students' Union, said it was "nothing new that student housing isn’t the best quality", but complaints were often not taken seriously".
"Research we’ve done in the last year has shown that rents are way too high, the quality is way too low, and students are struggling financially, mentally, physically," he said.
"It’s having an impact on their academic performances, which shouldn’t be happening in this day and age."
The Welsh government passed legislation in 2016 which set standards for landlords who lease their properties, and are currently considering a new law on fair rents.
Community and tenants union Acorn Cardiff are among the organisations who responded to a consultation on the topic last year, and are calling for rent controls being introduced.
"People are getting ripped off because they’re paying more than ever for these houses that aren’t suitable for them to be living in, or have got major issues and need repair," said Holly Firmin from the union.
She added: "[Rent control] is not going to solve all of the problems with the private rented sector.
"But introducing some kind of emergency rent control measure is at least going go some way to dealing with that immediate issue."
The Welsh government said: "The evidence submitted to the Green Paper clearly identified a need for better data on rents and affordability, and this is being considered as part of a White Paper planned for publication later this year.
"In Wales, we have put measures in place that limit rent increases to once in a 12-month period, provided two months' notice has been given, and the landlord is in compliance with all requirements under the Renting Homes (Wales) Act."
