Why Is Water Coming Down My Coaxial TV Aerial Cable?

March 11, 2022

Water Coming Down My Coaxial Cable – What To Do!


You may have noticed a brown stain on the carpet by your aerial cable or a green sort corroded TV aerial plug, or you might have a TV aerial plug that is stuck to your TV that you can’t pull out without damaging the TV. In all of these cases you most likely have a waterlogged TV aerial or satellite cable.


Obviously, this is a big problem where the waterlogged cable enters your TV or set top box as it could damage the TV. Fortunately, I have written this blog to help you figure out what to do next, with temporary measures to protect your TV and how to stop it happening again in the future.


Why Is Water Coming Down My Aerial Cable?


There are a few reasons why water could be coming down your TV cable, these are:


Damaged Cable

A coaxial cable can be damaged numerous ways, all that is required for water to start coming down your aerial cable is there to be a break in the PVC outer sheath. Especially when this is on a vertically part of the installed cable. Rainwater can run down the cable until it hits the break where it enters the cable and then slides down the inside of the coax to the TV position.


A cable can be damaged by obvious methods like an accidental cut or snip, or it can be caused by aggressive installation techniques where the cable has been damaged on installation. I have seen it on numerous occasions where the aerial cable has been fed behind guttering and obviously been caught which when pulled caused a break the outside of the cable jacket.


By far the most common reasons is where cables haven’t been secured properly, most common with cables running down roofs and over time with the wind blowing the cable it becomes chafed.


Old Cable

Cables over time naturally deteriorate in the sun, the sun leaks over the plasticiser which causes the cable to become brittle which is prone to snapping and cracking if handled. If left for long enough the cable will get lots of breaks in it which will allow water to enter the cable. This is most common with cables most exposed to direct sunlight, so cables running down the south side of the house roof and on the south side facing walls here in the UK, obviously the opposite would be true in the southern hemisphere in places like Australia and New Zealand.


Believe it or not this actually effects white cables more than black cables so if you have the choice of installing either it’s best to use black cable when installed outside. The cable itself can always be painted to match your wall and few things look worse than a white cable running down the roof.


Cable Not Been Weatherproofed Properly

When you connect a coaxial cable to an aerial or a satellite dish there is a point where the cable needs to connect to the antenna and here is a point where rainwater can enter your cable if the termination hasn’t been weatherproofed correctly.


It’s imperative that when installing a cable into an aerial or other antenna that the cable as it leaves the dipole is immediately angled down towards the ground to create a “drip loop”so that any rainwater will use the cable itself to enter the cable termination.You should also weatherproof with amalgamating tape any external connections and/ or use silicone grease for terminations on satellite dish LNB’s. Weatherproof coaxial F connectors can also be installed to prevent water ingress into the cable.


Lastly, make sure that the antenna that you’re installing is actually the correct way up. Many types of aerial do not matter but other’s do have a correct way and an incorrect way. I’m not just referring on the aerial mounting polarisation that changes between different transmitters, but the drain away air holes that are on some dipoles. Installing these the incorrect way instead of allowing rainwater and moisture to escape the cable termination it will actually provide an entry point to allow rainwater into the dipole and fill up with water.


Things To Do When You Have Water In Your Coaxial Cable 

Ultimately you need to replace your coaxial cable right back to your antenna or first point of termination, so you will need to purchase some good quality coaxial cable some plugs and cable fixings. If this involves accessing your roof you may want to contact a TV aerial company in your area to do this for you.


If your coaxial cable is in very poor condition, there is a good chance that your antenna is also in a poor condition as more often than not these are usually installed at the same time.In fact, with the fixings becoming old and rusty it may not be possible to connect a new cable without replacing your aerial.


Temporary Short Term Measures 

You absolutely do not want the water entering your TV as it could damage it. So, I would advise completely dis-connecting the cable and putting it into a small container as the aerial plug itself is likely to leak brown water which could stain your carpet but if you need the TV to be connected then you could try the following at your own risk.

1- Join the aerial cable or attach a flylead with a fresh section of cable that connects to your TV. This will usually force the water to collect in the join and not make it any further towards your TV.

2- Cut a section off the PVC away before it enters the TV and place inside a small container of glass. This will give the water an exit point before it enters the TV. You will need to be very careful when doing this that you only cut the PVC and not through the cable braid and into the centre conductor.


Tips For Preventing Water Ingress Into TV Aerial Cable & TV 

In this section I discuss some things that you can do to stop the cable becoming waterlogged again in the future.


Install Good Quality UV Stable Cables Outside 

I think most people just assume that the coaxial cables they install are suitable for outdoor use. Whilst this is usually true it isn’t always the case. Cables that are not designed for outdoor use will quickly fall apart when exposed to direct sunlight which will allow water in. This is actually most common with indoor only telephone and data cables being installed outside.


Avoid All External Joins 

Where possible try to avoid external joins altogether. If you have only TV, then it’s best to have a single section of coaxial cable connecting your TV aerial to your TV or radio aerial to your radio with no joins at all. Whilst a correctly weatherproofed coaxial join is usually fine,just by having one provides a weak point where water can enter the cable.



Weatherproof All Cable Connections & Terminations 

Like I already touched upon. Where there are external cable connections present like to the antenna itself, to aerial splitters & masthead amplifiers and with external joins you should ensure measures are taken to weatherproof connections. Tips on getting this right are:

1- Ensure that you have a drip loop when existing a cable termination

2- Use Amalgamating tape to weatherproof connections & cable joins

3- Use silicone grease on LNB and connections where amalgamating tape can’t be used.

4- Consider using weatherproof compression plugs.


Ensure the Cable Is Secure When Installed 

When installing the cable itself you need to ensure that adequate cable fixings are being used so that the cable doesn’t blow and around and move after installation. Some measures that can be taken are:

1- Be generous with insulation tape when connection cable to aerial mast.

2- Use tile clips, made from sections of lashing wire that sit under the tiles every few tiles so that cable remains in position when running down the roof.

3- Use cable clips or cable ties every 5-6 bricks vertically or two bricks horizontally to hold the cable in position.


Route Cable Internally Where Possible 

It’s a good idea where possible to route TV cables internally where possible. Often this creates a far larger job so expect to more on your aerial installation price if you want to be a bit creative when routing your aerial cable. This may mean routing a cable via the loft or under the floorboards/ in the walls rather than running the outside and then back in.I recommend checking our blog on how to hide TV cables for more information on this.


Drill All Holes Through Wall Slightly Downwards & Use Silcone 

It good be that the water which appears to be dripping from inside your coaxial cable is actually dripping from the outside. This is common with holes that have been drilled through a wall slightly upwards allowing the water to use to cable itself to get inside your property.


When drilling a hole through a wall, drill slightly downwards to prevent the water using the cable itself as a bridge into your property. The external hole should also be sealed with a blob of silicone. 


Install Wallplates

Although wall-plates won’t stop the coaxial cable or aerial cable becoming waterlogged. It will stop the cable inside that connects between the wall-plate and the TV or your set top box from becoming damaged by the waterlogged cable. This water will collect in the wall plate itself which obvious will need to be fixed but it will cost substantially less to fix than having to buy a new TV! Beneath are video guides on coaxial wall plate installation.

TV Aerial wallplate installation

Satellite wallplate installation


Any Questions? Please Ask 

I am more than happy to help with all of your TV, aerial,satellite & AV questions that you may have and not just regarding waterlogged TV cables. I just ask that any questions that you have are written in the BLOG COMMENT SECTION at the bottom. Please DO NOT CALL and please DO NOT E-MAIL as you will not get a response, or you will get one asking you to comment on the blog.I honestly can’t deal with all the questions that I get asked but by commenting on the blog it gives me a central location to manage them and also everyone gets to see the benefit of the question asked and the answer given, plus I do not have to answer the same question 100 times!


Until next time,



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