It was not until a friend told her of her rights that Karpuk realised she had been paying too much for water.
She felt powerless to do anything when her landlord refused to pay her share.
The tribunal ruled in Karpuk's favour, ordering her landlord to repay $567.12, but Karpuk believed she was owed more.
"That was all the invoices I could find. The general reckoning is $225 a year."
CARE Waitakere Trust budgeting mentor Iain Davies said many more cases were not taken to the tribunal.
Of the 300 clients the service saw each year Davies said about 60 had been paying more than they should.
Under section 39 of the Residential Tenancies Act it is the landlord's responsibility to pay for the fixed water charge - in turn the tenant pays for the water that is consumed.
MBIE's tenancy, compliance and investigation national manager Steve Watson said: "Landlords are responsible for ensuring there is drinkable water supply to the premises, but both landlords and tenants can be responsible for paying water and wastewater charges."
However, it appears the law is not so clear cut for the public with many unaware of their obligations or entitlement under law.
Davies often called his clients' landlord with a reminder of their responsibilities.
"Sometimes they say they are not going to do anything and at other times they are really apologetic and will work something out to pay it back."
In the published tribunal decisions the Herald viewed most seemed unaware of their responsibility.
Many applied to the tribunal with claims for damages against tenants - only to end up having to pay costs.
In early 2016 one landlord took a tenant of nine years to the tribunal asking for compensation when the carpet at her Bucklands Beach property was left smelling of cat urine.
While the landlord's claim was successful in part, the tribunal ordered the tenant be reimbursed $685.85, of a total $1361 in overpaid fixed water charges across six years.
In the most costly case so far this year, the tribunal found the landlord at a Henderson property "has been unaware of her legal obligation to only charge for water based on consumption".
The landlord was ordered to pay the tenants back the $766.16.
One landlord before the tribunal had sought to claim back money for unpaid rent and unpaid water.
When the issue of water came up the landlord admitted attempting to pass the bill on to the tenants by including it in the tenancy agreement.
The tribunal identified it as another example where "again there has been some confusion over water charges due".
"The law is clear on this point the landlord is not entitled to claim these charges and it appears the landlord has attempted to be less than clear on this point with his tenants."
However, New Zealand Property Investors Federation executive officer Andrew King said many were confused or unaware of their obligation.
He said this was because water had been treated differently from any other utility, with bills given to the landlord who had to pay it before recouping consumption charges from the tenant.
"For the benefit of tenants and landlords we think water should be treated like any other utility."
He called for a change to the law that would see water, including fixed water charges, charged back to the tenant in a single water bill.
However, Davies said it had to be the landlord's responsibility because it was a cost that was incurred whether the property was tenanted or not.
Tenants owed hundreds
In April 2017 an Auckland tenant went to the tribunal with claims against his landlord that included overpayment of fixed water charges he had paid in 17 months living at a Lynfield address.
Overpayment of fixed water charges: $286.45
In March an Auckland landlord sought payment for unpaid rent, water charges and cleaning costs. However, it was found the tenants had paid in excess of $200 for fixed water charges at the Mt Eden address.
Overpayment of fixed water charges: In excess of $200
In January a landlord claimed for damages and unpaid water bills. The tribunal found the tenants had overpaid fixed water charges by $766.16
Overpayment of fixed water charges $766.16
In October 2016, an Auckland landlord claimed for unpaid water charges, cleaning and removal of rubbish from a Pt Chevalier address. Howeverthe tribunal found over the 10 years of tenancy it was likely the tenants had paid more than the $1006.47 that was to be paid back. The landlord claimed it was an "honest mistake".
Overpayment of fixed water charges: In excess of $1006.47
In May 2016 an Auckland landlord claimed over unpaid rent and unpaid water charges from tenants at a Glen Eden property.
The tribunal ruled the law was clear that it was the landlord's obligation to pay for fixed water charges.
In March 2016 a landlord sought damages and while successful in part, ended up having to pay the balance of $685.85 (of a total $1361 of overpaid fixed water charges) to the tenants.
Overpayment of fixed water charges: $1361
