It may not be that important in the Summer when fish may be feeding in the upper waters but, personally, I think it is critical in the Winter.

Even when you think you know the water it always pays to double check.

I remember fishing the Total Fishing Knockout contest and drawing Nigel Harrhy ‘away’ at his match pool and plumbing up revealed two ‘holes’ that he hadn’t excavated midway between pegs under a slim rope. I fished to the holes for a convincing win.

likewise in the Winter when the sun is out a depth of around 2ft seems to warm quicker so I’d always look for a bit of the peg where I can have this.

Being ultra accurate with your plumbing will also bring you fish where bites are shy. I used to fish Parkerss Fishery in Bulkington a lot and if you weren’t at spot on dead depth you could convince yourself that there wasn’t a fish in your peg when fishing the pellet.

always nice to see if you have some feature, as opposed to “holes” you may have “tables” a raised plateau that may hold fish.
It is worth looking for anything, it may not make any difference, but it is worth giving it a go. ~think

Totally agree with the previous posts but beware of the dreaded ‘silt’ that can give a false reading. A lot of commercials have a thick layer of fish poo, rotten bait and general grunge on top of the real bottom of the lake. A heavy plummet will go straight through it and sit on the true bottom whereas you want your bait sitting on the top of it. Could be a few inches deep that grunge and that could be enough in winter to ensure you don’t see a proper bite.

By all means plumb up with a normal plummet but it is worth putting a light shot on the hook to check that you haven’t got a false reading when your happy with the area you will be fishing.

Plumbing up is the second most important thing after feeding correctly in getting the best from your swim at all times of the year. Even very small changes in depth can mean a fish holding area. Normally, shelves, bars and creases and deeper holes on the bottom are the fish holding areas in the swim. However, dragging your plumbit around your swim can show up weed and snags that can also be areas to target or places to avoid when playing fish. Its also nice to know that there are a few fish in my peg before the all in. By carefully dragging a plumbit around my swim. You can often get few line bites that give confidence and show the area of the peg that the fish are sitting. I probably spend 10+ minutes plumbing around my peg to get a good idea of whats on the bottom so i can identify the best areas to target the fish.

Quality info above Bram.The silt can be a big issue .Despite careful plumbing up at a local pond the way the rig settled was often erratic soon as you got near full depth.The jury may be out on the pro’s and con’s of dragging a swim with a rake and rope but its use can also give clues to the bottom itself.Using a old cheap pole with a landing net handle telescoped through it and a weed cutter blade on the end I dragged/ explored a swim I had just fished and safe to say i soon brought back various grades of weed from fresh and tough green stems to black rotted slimy stuff,where it wasn’t weed it was foul smelling sludge.
Like the lads above say if you can learn to recognise this as well as the actual overall underwater topograhy you should create a better picture.In some local venues like an old sand quarry a bladed cutter will bounce of the deck in this one it just dug deeper into the gunge.
Can imagine a full dendra burrying itself quite easy whereas something light and/or dead would lay on top/not get tangled up so easy eg punched bread/expander/dead maggot.
Ironically sometimes on a slope can be okay as it may be firmer than the collection gully at its base and fish may want to feed without upending themselves too far.Some commercials with sand/gravel bottoms in contrast have fish patrol routes where the bait rolls to the first flat spots.

Yes, any time of the year you should have a good plumb around but in winter it is vitally important.

im one of those who plumbs up for about 30 secs! lol
find a far bank marker and “that`ll do!”
if i dont get a bite ill move!
ive found in winter though fish seem to want to be either at the base of the near or far shelf, slightly up it if anything out of the sludge and have the bait in there face so to speak, or up in the water warming themselves up a bit if air temp is higher than water temp!

probs cost me a few fish this so message to self, spend a bit longer plumbing up!

give as much time as you possibly can to plumbing up its not time wasteing to read the swim first or even to keep checking the depth

theres some very good tips already given but one thing to remember is the position of the float lined up with markers as 6inches in any direction can give you the wrong depth

slopes are good to find as they can make it easy for fish to take the bait as its lodged against the slope

just bought some large sensas plummets they look the biss we will see

i feel that plumbing can make all the difference in getting the most out your swim. i plumb up not just to find out the depth but to see how im going to lay my rig in aswell.

say your fishing up a slope, no point laying you rig out in front of your pole tip and your bait sitting too far up the slope, better to lay it in before and push it into the slope giving you dead depth and the other way round if fishing a downward slope. if you find a small hole i would lower it staright in.

Do you think you can get carried away with the plummet and upset the fish in the swim ?

ive had em suck the plummet in!

I have had the plummet ride on the back of a carp

To answer to your question, Anthonywaters. No! Or, at least. Not if you are careful in the way you drag your plumbit around your swim. I dont often use a big plumbit because im usually looking for ledges and small changes in depth. I dont want my plumbit sinking in to the silt. When i drag my plumbit around my swim to see if i can find any fish. I do it very carefully and once the line makes contact with a fish. I stop moving the pole. I can often find the same fish or another fish in the same part of the peg if i do the same proses again. So, that suggests that if careful the fish are not spooked by the plumbit or by making contact with the line. It might be different if a big heavy plumbit is used as there would be more pressure on the fish we made contact with. Also, it you think about it. We set up our tackle in the hour before a match and do things like plumbing up. At the start of many matches. We often catch a few mug fish early before things get a little harder. That also suggests that plumbing up does not disturb the fish. In fact, plumbing up could in fact increase the chances of catching a few fish early because of the disturbance in the swim.