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Do Evaporation Lines Disappear on That Pregnancy Test of Yours? Know the Answers

Are you confused after taking that “peeing on a stick test” and finding a faint line?

Home test kits for pregnancy are pretty convenient. Things might become blurry sometimes, depending on the result. Finding a faint line on the result is quite common. What you are seeing might be an evaporation line. But do evaporation lines disappear?

Unfortunately, evaporation lines do not disappear. If you have tried to wash it out, you might have known by now that it’s of no use. However, it might get faded out after 48 hours or more.

There are several reasons why you see the line. If you are unsure what to make out of it, you should try another test. While going for another test, make sure to follow the guideline properly to avoid getting confused with false positive results.

Still feeling messed up? Stick along, and you will be cleared of the whole idea of this evaporation line.

Table of Content

Do Evaporation Lines Disappear?

Lines are always simple and straight. The evaporation line on that test kit of yours is simple as well. Though it might push you to a foggy situation, things will be clear once you know the facts.

Evaporation lines occur due to several reasons. They look faint, and you might mix them up, thinking to be a positive result. Knowing how to distinguish the line is essential to avoid false adverse outcomes.


If you wait for the line to disappear, that won’t do any good. The line generally does not disappear from the kit. Even if you try to wash it out, it won’t work. 

The faint lines can confuse, especially if you cannot distinguish them. So, if you find the evaporation line, you should try another test.

Identifying the lines – Positive and Evap

At-home pregnancy test kits are convenient if you follow the instructions carefully. Many people get confused when they find faint lines on the result. If you are the same and confused if the result is positive or not, you are in the right place. 

There can be some reasons behind that faint line. It can be a faint positive line or just an evaporation line. It can also result in false negatives if you don’t look closely. So you must know the difference between the fain positives, positives, and the evaporation line.


There are some ways you can tell the difference between the positive line and the evaporation lines. So here is how you can tell the difference.


Firstly to distinguish the positive line, check out its color of it. If the color of the line is the same as the control line, congratulations, you are positive.

The line can also show a faded color. But if the control line is pink, the positive line will also show a pinkish hue. 

If the line is faded with a colorless hue, it is an evaporation line. The evaporation would resemble water drops. They also don’t disappear even if you try to wash them.

But, are you seeing a line that is faint and pinkish? Confused if it’s an evaporation line or a positive one?

Well, a faint positive line is if you see a pinkish hue. It means that the human chorionic gonadotropin or HGC hormone is not yet concentrated enough, so you should try the test again later to ensure the result.

Line Thickness

The thickness of the line in the result window is another of distinguishing an evaporation line. If your look closely, the positive line should be the same as the control line. The thickness would be similar.

On the other hand, the evaporation lines have very inconsistent thicknesses. So if you get confused, you would need to examine the lines closely and figure out which line in which.

Result Time

The time for the lines to occur is another way to identify the positive line. The HGC hormone takes about 2-3 minutes to complete the reaction and show that line.

The evaporation line, however, shows up when you give a lot more time for the urine to evaporate. This can be approximately 10 minutes.


So If you check the kit after more than the reaction time, you might also find the evaporation line. And if you do evaporation lines disappear, then the answer is no. It will stay there even if you wash it.

Reasons For the Evaporation Line

Evaporation lines on at-home pregnancy test kits are some things that can screw with your head. You may confuse the kit’s result if you cannot distinguish the line. The result is a false positive in many cases.

There are quite a several reasons for the line o occur. Some of the most obvious ones are-

You’ve Waited Too Long

One of the most obvious reasons behind the evaporation line is the evaporation of the urine. Once the urine is evaporated, it leaves behind a faint colorless line. 

So, the urine needs enough time to evaporate for the line to occur. But the HGC hormone, which shows the result, takes about 2-3 minutes.

So if you leave the test kit for about 10 minutes, the urine will evaporate and give you the evaporation line.

Kit Sensitivity

Sometimes, the kits used are more sensitive to hormones and urine. In such a case, the evaporation of the urine impacts the test kit more easily. The kit reacts quicker and shows up with the evaporation line without delay.

Expired or Damaged Kit

Are you sure you are using a brand new kit? Have you checked if the kit was left open for a long time before use? 

Yes, such conditions can distract you by giving unusual lines. If the kit is damaged somehow, urine can flow inside the kit and leave behind a faint line. 

Preventing the Evaporation Line

Are you confused about whether to take that colorless faint line as a positive result or not? Or are you waiting for it to disappear? Well, to be honest, the evaporation line doesn’t mean that much. It’s just a mark of your urine left after being evaporated.

Evaporation lines are the result of several facts. If you are not sure if it’s an evaporation line or a faint positive one,  it is recommended that you take another test. But what if you find that line again? Yes, you can avoid the line from showing up.

Generally, if you see the evaporation lines, you are not following the test instructions carefully. You should go through the instructions again on the test kit and try it again.

There are also some handy tricks that you can follow besides the regular instructions. Such as

Use a Cup

Try not to urinate directly onto the test kit. Instead, you can use a cup or any small container. Then use it to pour the urine onto the kit. This is useful to prevent any unnecessary splashes.



Evaporation lines result from, as the name states, evaporation of your urine. So if you leave the kit for too long after the test, there is a huge chance you will find evaporation lines.

So, why not use a timer? You can simply use your phone to set a timer according to the kit’s instructions and see the accurate result when it’s ready.

Expiration Date

Always look for the expiration date on your kit. Also, check for any damages. These can easily result in evaporation lines and even false results.

First Thing In the Morning

The at-home test kit reacts to the HGC hormone in our urine. You might find faint positive and evaporation lines if your urine is diluted. So how do you make sure your urine is not diluted?

If you plan for the test, try doing it the first thing in the morning. Your urine will not be diluted, and you will get more accurate results.


Have you checked the storage instructions for your test kits? Are you sure you kept them as instructed? If not, the evaporation lines can occur if you are storing your kits in the wrong way.

Generally, the instructions state that 36-86°F should be the temperature you need to store your kits.


Has the evap line turned out to be positive?

An evaporation line, or evap line for short, is the outcome of urine evaporation. A pregnancy test kit reacts to the HGC hormone in the urine. So the evaporation line, like a colorless stain, has nothing to do with the positive result. You can simply disregard that.

Do evaporation lines disappear with water?

If you are trying to wash out the evaporation line you have found, it won’t be of much use. These lines occur when your urine evaporates and is unwashable. However, after 48 hours or so, you might find the stain much faded.


At-home pregnancy tests are pretty “heart quaking.” It can be more severe if you get bewildered about which line to read on the result window. Test kits react to the HGC hormone in your urine when you are positive for the pregnancy test. 

On the other hand, evaporation lines are stains from your evaporated urine. They are colorless, and you might not even notice them without looking closely. Only look for the positive line, similar to the control line. The evaporation line means nothing and can be ignored.

But there are ways you can avoid these evaporation lines. Make sure you check the quality of the test kit and follow the instructions. The result will be accurate. Good luck!

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