Green’s Dictionary of Slang

pisspot n.

also pee-pot, piss-barrel, pissing-pot, piss-tub
[piss n. (1) + SE pot/pee n.1 (1)]

1. [mid-16C+] a chamberpot.

2. [late 16C+] an unpleasant person.

3. [mid-17C; 1950s+] a drunkard.

4. [1970s+] a lavatory bowl.

5. [1990s+] anywhere unpleasant, dirty, smelly etc.

In compounds

Piss Pot Hall (n.) [Dr Henry Sacheverell (c.1674–1724) was a High Church and high Tory cleric, who preached two sermons in 1709 that resulted in his impeachment on charges of seditious libel. He was condemned, but received so light a punishment as to claim victory. His supporters were as vehement as the unknown potter. The Rector of Whitechapel commissioned an altarpiece in which the figure of Judas Iscariot was represented by that of the Dean of Peterborough, one of the Doctor’s most virulent critics]

[late 18C] ‘a house [? a tavern] at Clapton, near Hackney [in northeast London] built by a potter chiefly out of the profits of chamberpots, in the bottom of which the portrait of Dr Sacheverell, preacher, was depicted’ (Grose, 1788).

In phrases

know the pisspot from the handle (v.)

[1990s+] (US tramp) to be wise.