At night when the house is quiet I can hear water running through the pipes when I'm in the bathroom... it's quite loud but not noticeable in the day as radio is on normal house noises etc... if I put my ear to the washing machine I can also hear it there... for curiosity I turned off the stopcock and the noise stops... I want to contact the water board but my husband is against the idea as if they stump us with the bill we have no money to meet the charge
Any ideas what it could be and should we contact the water board... also do you think we would have to pay and if so how much is it likely to be

From the wording of your post, I assume that you are in either the UK or EU. All of the posters on this site are US. While water is water the world around, the way we do plumbing a little different. What you describe is almost certainly the symptoms of a leaking toilet. Water and the pipes transmit sound very well. Even though you hear the sound at the washing machine, it is being made by the toilet.

In the US, there is a stop valve at almost every point of use, including toilets. If that is true where you are located, and you have more than one toilet, you can determine which toilet is leaking by turning off the stop valve at each toilet and listening for the noise.

Toilets can leak for either of two reasons. They can leak because of a faulty fill valve or because of a faulty flush valve.

There are two types of fill valves. There is the older style called a ball cock. It is the type that has a large, round, plastic float on the end of a rod. When the water in the tank goes down, the float drops and turns the water on to refill the tank. When the water in the tank rises the ball turns the water off. The other type of fill valve is just referred to as a fill valve. It works the same as the ball cock but the float is around the shaft. The ball cock type can be repaired but is often simply replaced when defective. The fill valve type is very easy repaired. Neither the ball cock or the fill valve are very expensive.

The other part of the toilet that can leak is the flush valve. While there is several are types of flush valves they all operate basically the same. When you press the flush handle, a chain lifts the flush valve and water flows down into the bowl and causes the bowl to flush. The flush valve floats until all the water in the tank flows out into the bowl. When the water level in the tank drops and the fill valve refills the tank.

There are several types of flush valves. The most common is called a flapper because it is just a rubber flapper.

You can tell which valve is leaking from the sound. If the sound of running water is continuous, the fill valve is leaking. If the rubber washer in the fill valve or ball cock is defective, or there is some debris trapped in the valve, it will run continuously and the water will flow out the overflow tube. If you hear the sound of running water intermittently, that is your hear water running for a few seconds every 5 or 10 minutes, you have a leaking flush or flapper valve.

If the flush valve or flapper is defective, the water in the tank will slowly leak into the bowl. When the water level in the tank reaches a certain level the fill valve open and you hear the sound of running water.

An easy way to check for a leaking flapper is to remove the tank cover or lid. Hold down the float until water runs out the overflow pipe. Then turn off the stop valve under the toilet. Come back later and check the water level. If the water is still at the top of the overflow pipe the flapper is OK. If the water level is below the top of the overflow pipe, the flapper is leaking.

I, of course, would have no idea about water charges. In the US, the amount of water used is measured by a meter and you pay for the water that passes through the meter, regardless of where or not there is a leak.

More than you ever wanted to know about leaking toilets.

I have read your post several times and still don't know if you are complaining about noise from the drain or from the tap. Can you describe the noise? Can you furnish more details? Back to you, Tom

A simple test to see if the flapper is leaking is to drop 20 drops of a dark food coloring into the toilet TANK. If color shows up in the toilet BOWL within 1/2 hour to an hour then the flapper needs to be replaced.

Good luck!

Mark