It is widely distributed in lakes and rivers in the northern hemisphere, but is sensitive to poor water quality.

[7] The inflorescences are produced quite early for a pondweed, in May–June, and have 15–20 inconspicuous greenish flowers and held on robust peduncles 80–200 mm long.

[6] Potamogeton praelongus has a Holarctic distribution, occurring in northern Europe (Britain,[6] Ireland, Iceland, Scandinavia, Germany, Switzerland, France, Poland, Russia, the Baltic States),[11] Greenland,[12] Asia (Siberia, China, Korea, Japan),[7][11] and North America (northern US, Canada).

Long-stalked pondweed tends to be a rather rare plant within its range; for example, in a study of more than 3,500 British lakes, it occurred in only 88, most of which had low-moderate alkalinity and were dominated by isoetids.

[15] Long-stalked pondweed is relatively sensitive to eutrophication and declines or local extinctions of this species have been associated with increased nutrient levels.

[16][17][18] In Loch Leven (Scotland), P. praelongus was lost due to eutrophication during the mid 20th century, but has recently reappeared following improvements to water quality.

In the British Red List for Vascular Plants it is listed as Near Threatened[20] due in particular to a marked decline in southern Britain, likely linked to eutrophication;[21] assessments in England[22] and Wales[23] have recently categorised it as Endangered and Critically Endangered respectively.

[26] It is also listed as Endangered in Switzerland,[27] several US states[28] and some French départements,[13] Vulnerable in the Netherlands,[29] and Extinct in Flanders.

In common with other pondweeds of this group it roots poorly from stem cuttings and is best propagated by division of the rhizomes.

Its preference for relatively deep water and intolerance of turbid conditions may make it unsuitable for many garden ponds.