A MINISTER has said Southern Water's repeated failure is "totally unacceptable" after thousands of customers in the Southampton area were left without water. 

Around 13,000 properties were affected last week when an issue at Southern Water's Otterbourne site disrupted supplies in Southampton and Winchester. 

But now MPs have slammed the company's performance, calling for more investment in infrastructure. Company bosses were also summoned for a meeting with MPs.

Speaking in the House of Commons, Romsey and Southampton North MP Caroline Nokes said her constituents want significant fines when supplies are disrupted, asking the government to "force investment in the network". 

READ MORE: Southern Water: No water supply in Southampton again

Responding, water minister Rebecca Pow said: "I have been very clear that current water company performance is totally unacceptable and they must act urgently to improve their performance so that they meet government and customer expectations.

"The British people expect better and so does this government.  

"Whilst some supply interruptions cannot be avoided, this repeated failure to properly ensure customers continued water supply is totally unacceptable and I’ll be meeting with Southern Water’s CEO to understand how they plan to address their failings. 

"I want to be very clear that where water and sewage companies are found to be breaking the law, there will be substantial penalties."

Water outages lasted around four days last week. Bottled water stations were set up for the thousands who were affected. 

Daily Echo: Water stations set up as Southern Water customers experience outages.Water stations set up as Southern Water customers experience outages. (Image: Newsquest.)

It comes as more than 20,000 properties were left with low pressure or loss of water in December. 

Ms Nokes, Eastleigh MP Paul Holmes and Winchester MP Steve Brine were expected to meet with Southern Water today.

Speaking in the Commons on Tuesday, Mr Holmes said: "Twenty-thousand of my constituents were without water in Eastleigh before Christmas and thousands were last week.

"Clearly this stems from a chronic lack of investment in the infrastructure.

"One word not elaborated on is compensation. Will the minister contact the CEO to press that point and will the government up its game now in not asking water companies to invest in infrastructure, but force them to do so going forward?"

Ms Pow said there is a "clear compensation scheme," offering her help in ensuring this is understood and followed. 

READ MORE: How to get compensation if your supply was cut off

In a letter to Ms Pow, Southern Water chief executive Lawrence Gosden said systems shut down at Otterbourne after water quality had fallen. The on-site tank had to be drained, cleaned and disinfected before being refilled.

He added: "I recognise that this is a significant inconvenience to our customers so close to the event before Christmas."

Mr Gosden said vulnerable customers had been repeatedly contacted, and water tankers had been used to inject clean water into the system.