The water company’s profit before tax fell by £1.1 million to £86.2 million, for the six months to 30 September 2014.
Its sister waste management company Viridor, posted a drop in profits of £10.6 million to £4.7 million over the same period.
SWW saw its profit dip as a result of the tariff freeze it introduced for 2014/15, although the £11 million in lost revenues are set to be recovered in in the PR14 period (2015-20).
Alongside this, profits were hit due to customers switching to metered tariffs, which reduced revenue by £2.8 million.
SWW said it limited the impact of a £2.4 million increase in costs by finding £2.5 million of efficiencies within the business.
Pennon’s chairman Ken Harvey said SWW “is continuing its strong performance against the 2010-2015 regulatory contract” and that it “continues to deliver robust operational performance and efficiencies”.
He added: “With SWW’s track record of efficiency and outperformance, the company is well placed to deliver its business plan and will have an opportunity to outperform the assumed returns on equity.”
SWW chief executive Chris Loughlin said: “It was a good performance to overcome that price freeze in the year with no loss to shareholder value.”
SWW was one of two companies to be granted enhanced status and a fast track through PR14 by the regulator and received an early draft determination with a “do no harm” certainty for the Final Determination, due on 12 December.
Loughlin added: “We are not anxious of the final determination. We have had six to nine months to prepare to have a solid foundation to deliver our business plan.”
Pennon said its interim dividend is up by 6.3 per cent to 9.98 pence per share, reflecting the “continued underlying strength of the business and management’s expectations for long term growth”.