Emma Walkley, 38, of Empingham Road, Exton, received housing and council tax benefit after claiming to be a single parent and never revealed that her longterm partner had moved in.
She dishonestly claimed almost £12,500 in benefits and nearly £1,300 in council tax discount.
Walkley admitted five counts of benefit fraud when she appeared before Melton magistrates on Tuesday.
She was sentenced to a 12 month community service order, including 60 hours of unpaid work, and ordered to pay the outstanding over-payments of housing benefit in weekly instalments of £90.
Magistrates also made a compensation order of £1,298.98 in respect of the dishonestly obtained council tax discount, which she will pay in £20 a week instalments.
The sentencing marks the end of an 18-month fraud investigation conducted by Rutland County Council officers following an anonymous tip-off.
The chairman of the magistrates, David Penny, told Walkley when passing sentence: "Over a long period of time you have continued to defraud your fellow citizens."
Investigators found that Walkley's claims for housing benefit had never disclosed the presence of her long-term partner, nor had his presence been disclosed for the purposes of obtaining a 25 per cent single person's council tax discount.
The county council said in a statement that the offences had been going on since at least 2003.
The investigation into the fraud was sparked by an anonymous phone call to the county council's benefit fraud hotline, which receives about three calls a week.
The investigators carried out research with various agencies and visited neighbours of Walkley to gather evidence for the prosecution.
The first step in any investigation after a tip-off is to check that benefit is being received.
Once that is confirmed, the investigators can carry out credit checks, consult the Driver and Vehicle Licensing Agency, the Revenue and Customs authorities, the Department for Work and Pensions, police and other local authorities.
The Rutland investigators are working on about 50 cases at the moment, covering council tax and housing benefit frauds. They have teamed up with neighbouring authorities to enable 'cross-border' cases to be followed up.
Walkley declined to comment on the case.
Anyone who thinks someone they know is committing benefits fraud can ring the confidential 24-hour freephone fraud hotline on 0800 028 2196.