A sponging-house was a place of temporary confinement for debtors in the United Kingdom.
If someone were to get into debt, their creditor would lay a complaint with the sheriff, the sheriff sent his bailiffs, and the debtor would be taken to the local sponging-house. This was not a debtor's prison, as such, but a private house, often the bailiff's own home. The debtor would be held there temporarily in the hope that they could make some arrangement with the creditors. Anthony Trollope set out the system in his novel The Three Clerks of 1857:
He was taken to the sponging-house, and it was there imparted to him that he had better send for two things – first of all for money, which was by far the more desirable of the two; and secondly, for bail, which even if forthcoming was represented as being at best but a dubious advantage.
If debtors could not sort matters out quickly, they were then taken before a court and transferred to a debtor's prison.
Sponging-houses had a terrible reputation, which was made clear in a description by Montagu Williams, a London lawyer who knew them well, in his Down East and Up West of 1894:
Ah, my dear fellow, you´ve never seen a sponging-house! Ye gods – what a place! I had an apartment they were pleased to call a bedroom to myself certainly, but if I wanted to breathe the air I had to do so in a cage in the back garden – iron bars all round, and about the size of one of the beast receptacles at the Zoo. For this luxury I had to pay two guineas a day. A bottle of sherry cost a guinea, a bottle of Bass half-a-crown, and food was upon the same sort of economical tariff.
The idea of the sponging-house was based on that of the sponge that gave it its name, which readily gives up its contents on being squeezed. The sponging-house was the place where debtors had any available cash squeezed out of them, partly to the creditor's benefit, but also to that of the bailiff who ran it.
In French, “éponger une dette” (sponge-up a debt) means to repay one’s debt.
Notable sponging-house residents 
- Henry Fielding – author
- Michael Arne – composer
- Theodore Edward Hook – author
- George Morland – painter
- John Murray – Universalist minister